Left Side Pain: Causes and Treatment

Pain that persists or recurs on one or both sides signals an underlying problem to the body. Some common causes of left side pain are infection and injury to internal organs, muscles, or nerves.

In some cases, this pain will go away on its own. However, in other cases, immediate medical intervention may be required.

This article examines some conditions that can lead to left side pain. It also looks at the treatment options available and when a person should see a doctor.

The spleen is an organ located in the upper left side of a person’s abdomen. It’s an important part of the immune system, although people can live without it.

A person may feel pain on their left side when the spleen is injured or enlarged.

Damaged or ruptured spleen

A ruptured spleen is a medical emergency.

According to the National Health Service (NHS), an injury can cause the spleen to rupture. The rupture can occur immediately or weeks after the initial injury.

Symptoms can be:

  • Pain behind the left ribs
  • tenderness
  • dizziness
  • Fast heart rate

In addition, a person may feel pain in the top of the left shoulder when lying down and lifting their legs.

Enlarged spleen

Injury or infection can cause the spleen to enlarge. This can also be due to another health condition such as rheumatoid arthritis, leukemia, or cirrhosis.

The NHS advises that a person may not always experience symptoms. However, when symptoms do occur, a person may notice:

  • Discomfort and pain behind the left ribs
  • bleed easily
  • anemia
  • fatigue
  • quickly full
  • Infections


A person has to undergo an operation.

Find out more about the treatment options for an enlarged spleen here.

Diverticulosis is a condition in which small pouches form and penetrate through the weaker spots in the colon wall. Diverticulitis occurs when one or more of these pouches become infected.

The National Institute of Diabetes and Digestive and Kidney Diseases notes that the pain typically occurs in the lower left side of the abdomen.

The pain is usually sudden and severe. However, it can also be mild and worsen over a period of a few days.

Symptoms include:

  • diarrhea
  • constipation
  • Vomit
  • Nausea

Learn more about diverticulitis here.


When symptoms are mild, a person can rest, take antibiotics, and eat a liquid food.

After a few days, when the symptoms subside, the person can gradually return to solid foods in their diet.

If symptoms are sudden and severe, the person may need to stay in the hospital for a few days and be given intravenous antibiotics.

Find out more about the best foods for diverticulitis here.

A heart attack occurs when an artery that supplies blood to the heart becomes blocked. This blockage occurs due to a build-up of fatty deposits in the arteries.

Clogged arteries reduce the oxygen supply to the heart, damage the heart muscle, and lead to a heart attack.

Pain in one or both arms can be a symptom of a heart attack, but some other important symptoms to look out for include:

  • Discomfort in the middle of the chest
  • a feeling of squeezing pain or pressure in your arms, chest, or both
  • shortness of breath
  • cold sweat
  • Drowsiness

The American Heart Association (AHA) recommends calling 911 or the nearest hospital if you experience these symptoms. Many medical professionals consider the first hour of a heart attack to be the “golden hour” in which timely treatment can save lives.


Treatment for a heart attack usually includes surgery, medication, or a combination of both.

Find out more about heart attack treatment options here.

According to a 2020 article, sciatica is a painful condition that almost always affects only one side of the body. However, it can affect both sides of the body. This is known as bilateral sciatica, which is rare.

It is named for the sciatic nerve that extends from the spine to the legs and feet.

The most common cause of sciatica is a herniated or bulging disc that puts pressure on the sciatic nerve.

People with sciatica define the pain as “knife-like” or a sensation of tingling.

Some other symptoms are:

  • deafness
  • sharp pain when sneezing or coughing
  • an inability to sit up straight
  • weakness
  • a burning sensation around the buttocks

A specialist will perform a physical exam and ask about the person’s medical history to make a diagnosis. You can also do an MRI test to confirm the diagnosis.


Sciatica treatment includes rest, taking pain relievers, stretching, and in some cases, physical therapy.

With proper care, most people recover within 3–6 weeks.

A build-up of gas in the colon can cause pain on the left side of the body. The pain can also appear on the right side or on both sides.

Under normal circumstances, people give off gas by belching or through the rectum. This is a routine process for the body. In fact, most people produce about 1–4 liters of gas per day and give off about 14–23 times a day.

Sometimes gas builds up in the digestive tract when excess air is swallowed while eating or drinking. It can also accumulate through the breakdown of undigested food by intestinal bacteria.

Foods that can cause excess gas include carbonated beverages, sugar substitutes, and fiber supplements.

Other symptoms are:

  • frequent belching
  • flatulence
  • Flatulence
  • Pain or discomfort in one or both sides of the body


Treatment usually includes diet and lifestyle changes.

Find out more about simple remedies for gas here.

A doctor may also recommend over-the-counter (OTC) medications that aid digestion and relieve symptoms.

Learn more about painful gas treatment here.

A person may experience a strain or sprain on the left side of the body. However, it can affect other parts of the body as well.

Although people can use these terms interchangeably, strains and sprains are two different conditions that affect different parts of the body.

The NHS advises that it is likely a strain or sprain if the pain and other symptoms include:

  • ankle
  • wrist
  • foot
  • thumb
  • knee
  • leg
  • return

The National Institute of Arthritis and Musculoskeletal and Skin Diseases states that a sprain is a tear or twist in a ligament, which is elastic tissue that connects one bone to another.

Symptoms of a sprain include:

A strain is an injury to the muscle or tendon. It can cause partial stretching, and in some cases even tearing of the muscle or tendon.

To identify a strain, look for symptoms such as:

  • intense pain
  • Muscle cramp
  • Muscle weakness
  • swelling
  • cramps
  • Difficulty moving

Learn more about the differences between a sprain and a strain here.


The American Academy of Orthopedic Surgeons recommends similar treatments for sprains and strains. These are:

  • rest
  • ice cream
  • compression
  • elevation

A person may also need to do gentle exercise and take OTC drugs like acetaminophen, ibuprofen, or naproxen.

A ruptured ovarian cyst causes pain that typically occurs on one side of the body.

An ovarian cyst is a fluid-filled sac that can develop in or on an ovary. The Office for Women’s Health points out that these are common and usually harmless.

Ovarian cysts can burst. In some cases, they cause no symptoms or can cause mild symptoms. In other cases, the ruptured cyst can cause severe symptoms such as sudden and severe pain in the lower abdomen. Bleeding can also occur.


For milder symptoms, a doctor may prescribe pain medication.

In more severe cases, a person may need surgery.

Testicular torsion typically causes pain on one side of the body.

Testicular torsion occurs when the testicle rotates. This allows the spermatic cord to twist, causing blood to enter the scrotum. As a result, blood flow is reduced, causing pain and swelling.

Some symptoms are:

  • sudden and severe pain in the affected testicle
  • Nausea
  • Vomit
  • stomach pain
  • Groin pain
  • a swollen testicle

It is important to note that it is possible for the pain to come on slowly. This can extend over a period of hours or days. However, this is less common.


Testicular torsion is a medical emergency. If a man is not treated within 6 hours, his testicle can shrink and die.

You need to have an operation.

A kidney infection can cause pain on both sides or both sides of the body.

The kidneys are located on either side of the spine, below the rib cage. They perform many important tasks, including:

  • filter the blood
  • rid the body of toxic waste
  • control blood pressure
  • Maintaining the fluid level

However, these vital functions of the kidneys are disrupted in the event of an infection.

Kidney infection typically occurs due to bacteria. Most kidney infections start out as a bladder infection.

Symptoms of a kidney infection include:

  • Pain in the back, side, or groin
  • fever
  • Nausea
  • Vomit
  • cloudy or dark urine with an unpleasant odor
  • an increased need to urinate frequently
  • painful urination
  • chills

People with these symptoms should contact their doctor immediately.

Untreated kidney infections can lead to a life-threatening condition called sepsis. Up to 30% of people with sepsis die each year.


A doctor will prescribe antibiotics to treat a kidney infection.

Find out more about the treatment options for a kidney infection here.

If a person experiences symptoms of a heart attack, they need immediate medical attention.

A person should also see a doctor as soon as possible if they have symptoms of a kidney infection. If left untreated, the infection can worsen and lead to sepsis.

In general, it is important to see a doctor if the pain does not go away with home treatment or if it interferes with daily life.

Depending on a person’s symptoms and medical history, a doctor may recommend a visit to a specialist for a more thorough examination.

Pain is one of the body’s signals that something is wrong. There are different types and causes of left side pain.

Some of these conditions can calmly resolve on their own. Other cases may require medical treatment and long-term care.

The cause of the pain can be a disease or condition not included in the list above. It helps to be vigilant for other symptoms that accompany the pain and to report them to a doctor.

Try to estimate the beginning and end of the pain, its duration and its triggers. This information will help the doctor make a more informed diagnosis.