A range of health conditions may cause middle back pain on the left side including a sprain, kidney stones, osteoporosis, or pancreatitis.

The National Institutes of Health (NIH) is the source of the above information.

It is worth noting that the pain from these causes can manifest on the right side instead of the left side. The pain may also affect both sides of the back.

Various home measures may relieve the pain. Examples include moving the body properly when doing heavy lifting and doing exercises to strengthen the muscles that support the back.

This article discusses the causes of middle back pain on the left side, along with the causes of lower back pain on the left in females. It also examines how to relieve the pain at home, when to seek help, and answers to frequently asked questions.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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An array of causes may underlie pain in either the right side, the left side, or both sides of the middle back. They include causes that affect one or more vertebrae — the bones in the spine — and the structures surrounding them.

Other causes include conditions that affect the internal organs and miscellaneous medical conditions that affect the back. Details are below:

Structural and mechanical causes

These involve conditions that compress a nerve or affect structures in the spine, including the vertebrae, muscles, tendons, or ligaments. They can entail:

  • strain, an injury to a tendon or muscle
  • sprain, an injury to ligaments in the spine
  • spondylolisthesis, a condition where vertebrae get out of place
  • degenerative disc disease, conditions that lead to breakdown of the discs, the rubbery structures that cushion the vertebrae — this is likely due to aging
  • spinal stenosis, a narrowing of the canal that runs along the vertebrae, which can put pressure on a nerve
  • scoliosis, a lateral curvature of the spine
  • fracture (or break) in a vertebrae

Conditions affecting internal organs

Examples can include kidney infections or stones. Kidney stones are hard structures that sometimes form in the kidneys, and they can lead to serious health consequences.

Another cause is pancreatitis, or inflammation of the pancreas. The pancreas is a gland behind the stomach that plays a key role in blood sugar regulation. Pancreatitis can be a cause of pain in the upper abdomen that may spread to the back.

Miscellaneous medical conditions

These can include:

  • osteoporosis, a loss of bone mass that can lead to fractures
  • infections of the vertebrae or the discs between them
  • fibromyalgia, a condition involving widespread muscle pain and tiredness
  • ankylosing spondylitis, a type of arthritis that produces inflammation in the ligaments and joints of the spine
  • tumors, which rarely form on the spine or other places in the back

Endometriosis may cause long-term pain in the lower back in females. This can affect either side or both sides. In this condition, the lining of the uterus — or womb — grows in places in the pelvis that are outside of the uterus.


Back pain is common in pregnancy, and sometimes low back pain starts with the onset of pregnancy.

Learn more about back pain in pregnancy and how to relieve it.

The following home treatments can help:

  • Over-the-counter pain relievers to apply to the skin or take by mouth may provide temporary relief.
  • Cold packs may reduce some back pain, and hot packs can boost blood flow and promote healing in the back muscles and tissues.
  • Certain exercises can strengthen back muscles and improve posture, but a person should talk with their doctor or physical therapist before starting.
  • Moving the body properly — particularly when engaging in heavy lifting, pushing, or pulling — can help prevent strains that cause pain.
  • It is beneficial to engage in healthy lifestyle practices, such as:
    • getting enough sleep
    • quitting smoking
    • eating a nutritious diet

It is time to seek help if the pain does not decrease after a few weeks. Also, if medications do not help or the pain does not improve after an injury or fall, it is best to get medical attention.

The following are some commonly asked questions on the topic:

Is middle left back pain serious?

Conditions that produce back pain are varied, so when it occurs, it is not necessarily a cause for concern. However, it sometimes does indicate the presence of a serious condition.

What causes a stabbing pain in the upper back left side?

This can be a symptom of a heart attack. The heart lies on the left side of the upper chest. When a blood clot obstructs blood flow in the heart, a person may feel pain in the left side of the upper back.

If a person has other symptoms, they should call 911 for immediate medical attention. These include:

  • chest pain
  • shortness of breath
  • weakness

Stabbing left upper back pain tends more often to be a musculoskeletal issue.

What are the red flags for middle back pain?

If the following symptoms co-occur with middle back pain, it may mean that the cause of the pain is serious or requires medical care:

  • tingling and numbness
  • trouble urinating
  • fever
  • pain, weakness, or numbness in the legs
  • unintended weight loss
  • blood in urine

Middle back pain on the left side may stem from causes that affect the structure and mechanics of the spine, including the vertebrae, tendons, and surrounding muscles. It can also be a symptom of conditions affecting the internal organs— such as kidney stones — or result from other medical conditions, such as fibromyalgia.

Endometriosis and pregnancy can cause lower back pain in females.

There are things a person can do at home to help. Examples include doing back strengthening exercises and using cold and heat packs.

A stabbing pain in the upper back on the left side may be a sign of a heart attack — especially if someone has other symptoms, such as chest pain. This is an emergency and requires immediate medical attention.

If an individual has pain in other parts of the back that lingers longer than a few weeks, they should see a doctor.