Sharp, aching pain that hits on the left side of your breastbone and gets worse when you breathe deeply or cough could be costochondritis—a condition marked by inflammation of the cartilage that ...
Ross. “Physical therapy can also be helpful for muscle or nerve-related causes of left-side chest pain,” she notes, but mostly, she recommends rest for any strain-related causes of muscle pain.
Arm pain can have many causes, but left arm pain particularly can sometimes be a sign of a serious problem with your heart — especially if it's accompanied by chest pain or tightness.
In all CHD cases (179 patients) and all other etiologies (1032 patients), the pain is mainly situated in the left anterior thoracic region between the sternum and the anterior axillary line.