Paroxysms of pain occurring in the left side of the chest, considering breast disease, heart or lung-related aspects of the problem, the reasons are: first, non-menopausal women often have breast hyperplasia, hormone secretion with menstrual changes caused by, can not be rushed to treatment. It is not necessary to treat it urgently. Just pay attention to observation. Secondly, breast tumor is considered, which may be accompanied by roughness and unevenness of the skin outside the breast. Thirdly, transient myocardial ischemia caused by overwork and mental stress often occurs in middle-aged and old people, radiating pain to the left shoulder, which often lasts for 3-5 minutes. Appropriate rest, relaxation, there will be relief later, considering the external stimulus, coupled with their own cardiovascular underlying disease, such as vascular blockage, blood supply vessels spasm, resulting in lower blood pressure, lack of blood supply to the heart muscle. Fourth, the respiratory system, consider the bacterial infection viral infection caused by upper respiratory tract infection, often produce violent cough, the two layers of pleura will continue to friction produce inflammation and chest pain.