What is causing pain in upper left arm above elbow when I breath out after a deep breath?

Pain felt during breathing could be due to referred pain, where discomfort from organs manifests in other body parts, such as the heart, lungs, or diaphragm being felt in the arm. Musculoskeletal issues, like strains to the muscles or tendons in the chest, can lead to pain when the chest wall moves during breathing.

Nerve compression in the neck can sometimes result in pain radiating to the arm. Inflammation of the thin membranes covering the lungs, known as pleurisy, can lead to sharp chest pain that might also be felt in the arm and tends to worsen with deep breathing.

Conditions like anxiety or panic attacks might also manifest as physical symptoms like arm pain. It's also worth noting that, in some cases, arm pain can be associated with heart problems, although such cases usually present with other symptoms like chest pain or shortness of breath.

Given the complexity of potential causes, it's essential to consult with a doctor about your symptoms. If you have severe pain or any alarming symptoms, seek medical attention immediately.

Let us know what your doctor told you.