Pain under the left breast can have a range of causes from digestion to heart conditions. Home remedies may be enough to treat some conditions, but others could require medical attention.

Organs in the upper left region of the body may be the source of pain under the left breast. These include the:

The most common causes of pain under the left breast are often grouped into different categories, including:

  • heart-related
  • digestive
  • breast-related

This article looks at the different causes, symptoms, and treatments of pain under the left breast.

A heart attack happens when the blood supply to the heart suddenly becomes blocked. This is often caused by a blockage in a nearby artery. As the heart is situated slightly to the left of the midline in the upper body, pain under the left breast may indicate a heart problem.

It is estimated that every 40 seconds someone has a heart attack in the United States.

Is it a heart attack?

Heart attacks occur when there is a lack of blood supply to the heart. Symptoms include:

  • chest pain, pressure, or tightness
  • pain that may spread to arms, neck, jaw, or back
  • nausea and vomiting
  • sweaty or clammy skin
  • heartburn or indigestion
  • shortness of breath
  • coughing or wheezing
  • lightheadedness or dizziness
  • anxiety that can feel similar to a panic attack

If someone has these symptoms:

  1. Dial 911 or the number of the nearest emergency department.
  2. Stay with them until the emergency services arrive.

If a person stops breathing before emergency services arrive, perform manual chest compressions:

  1. Lock fingers together and place the base of hands in the center of the chest.
  2. Position shoulders over hands and lock elbows.
  3. Press hard and fast, at a rate of 100–120 compressions per minute, to a depth of 2 inches.
  4. Continue these movements until the person starts to breathe or move.
  5. If needed, swap over with someone else without pausing compressions.

Use an automatic external defibrillator (AED) available in many public places:

  1. An AED provides a shock that may restart the heart.
  2. Follow the instructions on the defibrillator or listen to the guided instructions.
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Treatment options will depend on when the symptoms start and how soon the person having the attack can access the first stage of care.

If the cause of the attack is found to be a blocked coronary artery, the doctor may recommend a procedure called an angioplasty to open a blocked or severely narrowed coronary artery with a balloon and possibly place a stent.

Angina

Angina occurs when the heart muscle does not receive enough oxygen in the coronary artery blood supply. This may cause pain under the left breast or in the center of the chest, which may also:

  • spread to the arms, jaw, or neck
  • feel tight, heavy, or sharp
  • be triggered by physical exercise
  • stop soon after resting

Other symptoms of angina include:

Angina is a possible symptom of severe underlying heart disease, so anyone experiencing symptoms of angina should seek medical attention immediately.

Treatment may involve prescribed medications, such as:

Pericarditis

The heart is surrounded and protected by a thin, layered, fluid-filled membrane called the pericardium. Pericarditis occurs when this becomes inflamed due to infection or a disorder where the body’s immune system attacks itself.

Symptoms of acute pericarditis include:

  • sharp, stabbing pain under the left breast or in the chest
  • pain in one or both shoulders
  • pain worsening when taking a deep breath or lying down on the back
  • feeling hot, sweaty, feverish, light-headed, and short of breath

Immediate treatment for pericarditis may include over-the-counter (OTC) anti-inflammatory medication like ibuprofen and rest until feverish symptoms decrease.

If a person experiences severe pain, a doctor may prescribe a steroid like prednisone. A person may also need to stay in the hospital for monitoring.

Gastritis

Gastritis is when the stomach’s lining becomes inflamed. Not everyone experiences symptoms, but a sharp, stabbing, or burning pain under the left breast is a potential clue that gastritis may be present.

Pain may also be accompanied by:

Treatment for gastritis will depend on its cause and whether it is acute or chronic.

Some medications may include:

Some home remedies may also help alleviate symptoms, including:

  • reducing alcohol intake
  • eating smaller portions more often, as opposed to one big meal
  • cutting out dairy, spicy, fried, or acidic foods, and caffeinated drinks
  • cutting down or giving up smoking
  • reducing high intake of OTC non-steroidal anti-inflammatory drugs (NSAIDs)
  • eating foods high in fiber and plant nutrients

Pancreatitis

Pancreatitis is inflammation of the pancreas. Acute pancreatitis has symptoms that include:

Chronic pancreatitis, where the condition worsens over time, has symptoms including:

  • frequent or prolonged episodes of pain under the left breast that can spread to the back
  • nausea and vomiting
  • oily, pale-looking stools
  • diarrhea

For acute pancreatitis, immediate treatment includes:

  • intravenous fluids to aid in hydration and ensure the body’s other organs have good blood flow
  • giving intravenous pain medication or antinausea medication

Treatment for chronic pancreatitis ranges from pain management and using increasing strengths of medication, to surgery if pain under the left breast is still severe.

Heartburn

Heartburn happens when stomach acid travels back up the food pipe and causes a burning sensation in the mid-chest and throat, and sometimes pain under the left breast.

Heartburn may be a symptom of indigestion and stomach acid issues.

Symptoms include:

  • a tight, burning sensation in the upper chest or throat that sometimes travels under the left breast and the jaw
  • a bitter taste in the mouth
  • pain under the left breast or in the chest while lying down or just after eating

Treatment for heartburn may include a combination of medications like antacids and home remedies, such as:

  • not eating big meals
  • not lying down to sleep right after eating
  • raising one’s pillow

Pain under the left breast may also be caused by breast trauma, infection, or hormonal changes.

Breast surgery

Different types of breast surgeries may cause pain under the left breast, including:

Depending on the type of surgery, it may take up to 6 weeks to fully recover.

During this period, a person may feel the following symptoms:

  • pain in the shoulder, arm, and neck of the area that got operated on
  • swelling and bruising
  • change in sensation
  • discoloration
  • scarring

In some cases, people may experience an infection which could cause pain, sickness, and oozing from the wound. If a person notices signs of an infection, they should get medical help immediately.

Milk duct conditions

Milk ducts carry milk from a person’s mammary glands to their nipples when they are breastfeeding.

Some conditions may develop inside the left milk ducts and cause pain under the left breast, including:

A person should see a doctor if they:

  • notice a lump in their breast
  • experience heat, swelling, and tenderness in the breast
  • have a clogged duct that does not go away after two days
  • have fever-like symptoms

Injury

A traumatic breast injury to the left breast may also cause pain. It does not, however, cause breast cancer as is commonly believed.

Common causes of breast injury include:

  • being hit while playing sports
  • falling
  • a car collision
  • repetitive movement of the breast, such as running
  • using a breast pump
  • breast surgery

In some cases, traumatic breast injury may also cause a breast hematoma to develop.

A person should get medical help if they suffer a traumatic breast injury.

Pleurisy

The lungs are surrounded by a layered membrane called the pleura. Pleurisy is when the pleura surrounding one or both lungs becomes inflamed due to infection or another cause, such as:

Pleurisy of the left lung may result in pain under the left breast.

The most common symptom of pleurisy is a sharp chest pain when taking a deep breath, but it can also be accompanied by:

  • pain in the shoulder
  • a dry cough
  • shortness of breath

The pain can get worse when the person walks around, coughs, or sneezes.

Treatment for pleurisy will depend on the severity of the condition and symptoms.

If a person experiences particularly severe chest pain, they should seek immediate treatment from a doctor, who may prescribe NSAIDs or other pain-relieving medications.

A doctor may also carry out further tests, such as:

Pleurisy caused by a viral infection often gets better after a few days, but a bacterial infection will require antibiotic therapy.

Spleen

The spleen can cause pain under the left breast if it is enlarged or if it bursts following an injury.

Symptoms of an enlarged spleen include:

  • tenderness and pain under the left breast
  • feeling uncomfortable when eating even just a small meal
  • anemia and extreme tiredness
  • bleeding easily

A burst spleen will typically cause:

  • pain under the left breast or ribs
  • tenderness when touched
  • bleeding
  • dizziness and fast heart rate

If a person suspects a burst spleen, they should get immediate medical help. Bleeding can be life threatening if left untreated.

A doctor will check for an enlarged spleen by feeling the abdomen and may recommend further testing through blood testing or imaging, such as an abdominal ultrasound, CT scan, or MRI scan.

Underlying conditions such as chronic liver disease and subsequent cirrhosis can affect and interact with the spleen.

A doctor will prescribe medication when medical therapy is possible to treat splenic or liver disease. Surgery is only required if underlying causes cannot be diagnosed clearly, or if complications arise from the enlarged or damaged organ.

During pregnancy

Pain experienced under the left breast during pregnancy may be caused by pressure from the top of the uterus as it grows, or if the baby is kicking or punching the expectant mother. The pain can be worse when leaning forward.

Muscles and other tissues will stretch as the baby grows, and this may also cause pain under the breasts.

The expectant mother’s body changes during pregnancy. As the baby grows, the internal organs will be pushed and moved, the rib cage may change position, and the expectant mother may experience heartburn with acid reflux.

Some conditions can be treated at home with rest and OTC medication, but people should seek medical attention straight away if:

  • the chest is injured
  • the pain under the left breast is unexpected
  • symptoms of pain and tightness do not get better with rest
  • shortness of breath, feeling sick, or profuse sweating accompanies the pain

Should I be worried if I have pain in my left breast?

Pain in the left breast may go away without treatment. However, it may also be a sign of an underlying condition that needs medical treatment. A person should see a doctor if they experience:

  • trauma to the breast
  • sudden, severe, or unexpected breast pain
  • swelling, tightness, or tenderness that does not get better with rest
  • shortness of breath, feeling sick, or profuse sweating that accompanies breast pain

What organ is under the left breast?

Organs in the upper left section of the body include the:

  • stomach
  • heart
  • lungs
  • ribs
  • colon
  • pancreas
  • spleen

What causes pain under the left breast?

There are numerous different causes for pain under the left breast, including:

  • heart-related causes, such as angioedema and heart attack
  • digestive causes, such as gastritis and pancreatitis
  • breast-related causes, such as breast trauma or clogged milk ducts
  • other causes, such as pleurisy

Pain under the left breast is often frightening to experience. Early diagnosis will increase the chances that treatment and recovery will be successful.

A heart attack is not the most common reason for pain under the left breast, but it is always better to have the symptoms checked out, especially if other symptoms of a heart attack are present.