Left side lying chest pain, consider the symptoms of cystic hyperplasia of the breast, and at the same time touching the breast lump by the hormone level, excessive proliferation of the breast appear swelling, tingling discomfort. When lying on one side of the local pressure pain symptoms, if the symptoms are relatively mild can be symptomatic drug treatment, to the hospital to do ultrasound examination to confirm the diagnosis, the local mammary gland by the impact, extrusion and other traumatic injuries, the local soft tissue damage with the position change pulling can also be pain, the local hot compresses symptoms can be relieved. Acute mastitis can also appear breast pain, with the position change local pressure symptoms can be aggravated, need to take oral antibiotic medication. You need to exclude chest wall infections or lung infections, chest pain caused by pleural effusion, and pain caused by stimulation of the location of the effusion when the position changes. Usually pay attention to wear breathable, comfortable, cotton underwear, to the hospital for ultrasound examination.