Side Chest Pain (One Side, Both Sides) Causes

The chest is contains several organs and structures. Some of these organs are vital for sustaining life, such as the heart and lungs. Therefore, pain in the chest could arise due to multiple causes. When pain arises on one side of the chest, the reasons may usually be traced to the lungs, pleura, or structures on that side of the chest wall (such as the ribs, muscles, cartilage, and skin).

The breastbone (technically known as the sternum), which lies in the center of the chest, is usually not involved with side (lateral) chest pain. It is important to note that not all pain felt on one side of the chest originates in that region. Sometimes, pain that originates from the central part of the chest (or other places in the thorax or the abdomen) may be referred to the sides of the chest as well.

Read more on central chest pain.

Causes of Side Chest Pain

The following are some of the probable causes of chest pain that is felt only on one side of the chest. It is important that chest pain is assessed by a medical professional. Due to the presence of vital organs within the chest cavity and the high incidence of conditions like coronary artery disease these days, chest pain can at times be a very serious symptoms.

Bone fracture

The chest cavity is enclosed within a bony structure known as the rib cage. The ribs (or bones of the rib cage) are long, curved and flat bones that are susceptible to fracture in case of a violent trauma. Fracture of the ribs can be a potential cause of pain on one side of the chest, especially if the pain is preceded by some violent trauma such as vehicle accident, collision during sports, a blow to the rib cage, a fall, or even a tight hug.

Collapsed lung

A blunt or sharp injury to the lungs (caused by fracture of the ribs, penetration of a sharp object into the chest cavity, certain diseases of the lungs, and certain medical procedures) can lead to a condition known as collapsed lung (technically known as pneumothorax).

In pneumothorax, air from the lungs escapes into the space between the lungs and the chest wall. This space is technically referred to as pleural space. This abnormal air pocket leads to the collapse of the lung, leading to difficulty in breathing. A lung collapse is typically accompanied by sudden onset of pain on the affected side of the chest and shortness of breath. If left untreated, pneumothorax can cause death.

Strained muscles

The main skeletal muscles of the chest include the pectoral muscles and the intercostal muscles between the ribs. A muscle strain or a muscle tear in the pectoral or intercostal muscles can also cause one-sided chest pain. Strain or tears in these muscles can occur due to strenuous exercise (such as weight-lifting), strained breathing or persistent coughing.

Inflamed cartilage

In addition to bones, the rib cage also contains a fair amount of cartilage. This cartilage connects the ribs to the breastbone (sternum). Inflammation of these connecting cartilages can also lead to one-sided chest pain. An example is costochondritis (also known as the Tietze’s syndrome), which affects the costal cartilages and the joints of the breastbone. Inflammation of the cartilage can occur due to injury, strain and inflammatory conditions such as rheumatoid arthritis.

Compressed nerve

The muscles of the rib cage are innervated by intercostal nerves. Compression of the intercostal nerves or an injury to the intercostal nerves can also cause one-side chest pain.

Lung infections

One-sided chest pains can also occur due to a variety of lung infections. Examples include pneumonia and pulmonary tuberculosis. Pneumonia refers to an infection of the air sacs in the lungs, which results in fluid and pus accumulation within one or both lungs.

This condition can become lethal if left untreated. Pulmonary tuberculosis is an infectious disease caused by the bacteria Mycobacterium tuberculosis. Many people who are infected with this bacteria do not show any symptoms. However, they can still spread the disease. Long-term antibiotic treatment is required to cure this disease.

Inflamed airways

An example of a condition that causes one-sided chest pain due to airway inflammation is bronchiectasis. In broncheictasis, there is permanent damage and enlargement of the airways, resulting from bacterial infections, prolonged inflammation, cystic fibrosis and pneumonia. There is an accumulation of mucus in the airways, which provides an ideal condition for bacterial infections to occur.

Inflamed pleura

The lungs are covered by a membranous sac known as the pleura. Inflammation of the pleura (technically known as pleuritis) may also result in one-sided chest pain. Pleural infections may occur during tuberculosis and pneumonia.

Viral infections

Apart from bacterial infections of the lungs, some viral infections can also cause one-sided chest pains. Examples include shingles and Bornholm’s disease. Shingles is caused by the virus, Herpes zoster. The pain in shingles is due to nerve injury caused by the virus. Bornholm’s disease is caused by the Coxsackie group B virus. A characteristic features of this disease is muscular pain (technically known as myalgia).


A variety of cancers can also lead to one-sided chest pains. Lung cancer is a malignant, uncontrolled growth of cells in the lungs that causes chest pains, bloody coughs, breathing difficulties, and weight loss. The most common cause of lung cancer is smoking. Even chronic exposure to second hand smoke can result in lung cancer. In some cases, the cancer may not originate in the chest cavity, but may metastasize from another primary site to the ribs.


Mesothelioma is a rare but aggressive type of cancer that mainly develops from the linings of the lungs and the chest wall. Mesothelioma may also develop from the linings of the abdomen, heart, and testes. The main cause of this cancer is exposure to asbestos.

Pulmonary infarction

Cessation of blood supply to a tissue starves that tissue of oxygen and results in the death of the tissue. This is known as infarction. Pulmonary infarction refers to the death of lung tissue due to lack of oxygen. Blockage of arteries in the lungs caused by a blood clot (technically known as pulmonary embolism) is a common cause of pulmonary infarction.

Connective tissue diseases

Some diseases of the connective tissue (such as systemic lupus erythematosus) may also cause one-sided chest pains.

Referred pain

Not all causes of chest pain originate in the chest region. Sometimes, pain from other regions of the body may get referred to the chest area as well. For example, various conditions affecting the heart, esophagus, bronchi, stomach, mediastinum, liver, and colon may cause one-sided chest pain.

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