Left chest pain in adolescence may be normal physiological pain, or it may be a symptomatic manifestation of some diseases, such as mastitis, intercostal neuralgia, etc. If persistent or progressive pain occurs, you should consult a doctor in time to find out the cause of the disease. 1. Physiological pain: Adolescent women may experience menstruation, due to the sudden increase of estrogen, which may cause slight swelling of the breasts and symptoms of left breast pain, which is a normal physiological phenomenon. This is a normal physiological phenomenon. After the onset of menstruation or menstrual period, it can be relieved on its own, and generally does not require special treatment. 2. Pathological pain (1) Mastitis: Chest pain during puberty usually belongs to non-lactating mastitis. Non-lactating mastitis is more common in young women and may be related to obstruction of milk ducts, infection, smoking, breast trauma and other factors. Patients may have the symptom of left chest pain, which may also be accompanied by localized breast lumps, nipple discharge, etc., and may form abscesses secondary to acute infection. (2) Intercostal neuralgia: It is mainly caused by degeneration of thoracic vertebrae, viral infection and rib fracture. When a branch of the left side of the nerve onset, the symptoms of chest pain can appear, the pain is mostly cut-like, needle-like, can be radiated to the back of the thoracic spine, usually in coughing, sneezing, deep inhalation aggravated. The symptoms of left chest pain in adolescence, after excluding physiological factors, should be timely consultation, clear diagnosis, and targeted treatment by the doctor.