Why Do I Have the Pain Only on My Left Shoulder?

The causes of left shoulder pain can be due to issues with the muscles or bones around the shoulder, or less commonly due to causes in areas other than the shoulder itself.

Shoulder and neck problems

When the pain intensifies upon moving the right shoulder, it is often due to issues with the muscles or bones around the shoulder joint. Pain can also radiate from the neck into the shoulder due to a pinched nerve or tight muscle in the neck.

Frozen shoulder

Frozen shoulder can lead to pain because the capsule covering the shoulder joint gets stiff. As a result, you can lose movement in the shoulder due to the all the inflammation. It can take several months for the shoulder to “thaw” and get back to normal range of motion.

Fracture

Fractures of the humerus, scapula, or clavicle cause acute severe pain in the shoulder.

Cervical disc hernia

When the cushions (intervertebral discs) between the neck bones are damaged, it can lead to pain or even compression of the nerves leaving the spine. While the pain originates from a problem in the neck it ends up causing shoulder pain.

Cervical spondylosis

Cervical spondylosis occurs when the bones, cartilage, and ligaments of the neck slowly degenerate over time often with age or increasing wear-and-tear. This condition can then lead to nerve compression which leads to pain in the shoulder.

Problems with Internal Organs

Less commonly, left shoulder pain may result from what is known as “referred pain”. Referred pain is pain coming from a deeper internal organ that ends up causing pain in another part of the body. In the case of left shoulder pain, diseases of the heart and lungs can cause referred pain to the shoulder. Unlike pain in the right shoulder, gallbladder issues do not refer to the left shoulder.

Heart disease

In diseases where the blood flow to the heart worsens, such as angina and myocardial infarction, you may feel severe pain in your shoulder. In the case of aortic dissection, a condition where the aorta tears, you may similarly feel intense pain in your shoulder as a result of referred pain.

Lung disease

There are cases where diseases of the left lung, such as pneumonia, lung cancer, or pneumothorax (air in the chest cavity that compresses the lung) are the cause.