There are several specific causes of pain in one side of the breast: 1. neurosis. For example, suffering from depression or schizophrenia, will be manifested in the body, appearing abnormal sensations, need to carry out drug treatment at the same time psychological intervention. 2, breast injury. The first of these is the use of the “physiotherapy” method of massage or the spraying of Yunnan Baiyao, which is used to stop bleeding and prevent infection. For example, myocardial ischemia or angina leads to discomfort in the left side of the chest, manifested as breast pain. It is necessary to maintain a stable emotion and go to the hospital for relevant examinations for treatment. 4, breast disease. For example, breast enlargement, breast fibroids, mastitis or breast cancer. For breast enlargement, you can take prolotherapy pills; for breast fibroids, you can have surgery to remove them; for mastitis, you need to empty the milk and anti-inflammatory treatment; for breast cancer, you need surgery plus chemotherapy.