Breast nodule pain in a 16-year-old girl may be normal, but it may also be related to causes such as cystic hyperplasia of the breast, mastitis, fibroadenoma of the breast or breast cancer. 1. Breast nodules can be found during self-examination or physical examination, and can be related to a variety of factors including endocrine and genetic factors. Adolescent females may experience pain caused by engorgement and hyperplasia of the mammary glands before menstruation, but the pain can be gradually relieved with the end of menstruation. 2. Adolescent women may have simple cystic hyperplasia of the mammary glands due to high levels of estrogen in the body, which may be palpable as a lump in one or both breasts, and the lumps may be painful during menstruation, and the swelling and pain may be cyclical with the menstrual cycle. 3. Mastitis: the cause may be related to milk stagnation and bacterial invasion, patients may have breast pain, localized redness, swelling and fever, and the lymph nodes on the diseased side may be enlarged and have pressure pain. 4. Breast fibroadenoma: Most of them are single, usually painless lumps, but if there is a lump that grows faster, it can cause local tingling or swelling. 5. Breast cancer: painless, single small lumps often appear on the side of the disease in the early stage, but if there is hyperplasia of the surrounding glands, it can cause pain. For adolescent female breast nodule pain, it is recommended to consult a doctor in time, who will make a diagnosis according to the clinical manifestations and examination of the condition, and carry out symptomatic treatment.