Developmental breast pain when pressed may be a normal physiological phenomenon, may also be caused by pathological diseases, common breast hyperplasia, mammary fibroadenoma and so on. 1. Normal physiological phenomenon: after a girl enters the developmental period, the level of estrogen secretion in the body will increase, the breast begins to develop, the breast tissue expands, the areola of the breast becomes larger, the color of the nipple areola deepens, and the process can be accompanied by tenderness and pain and other discomforts, which is the main cause of the pain of the girl’s developing breasts when pressed. 2. Mammary gland hyperplasia: As girls are in the early stage of development, the hormone secretion rhythm is not yet perfect, and they are prone to endocrine disorders, menstrual disorders, etc. In this case, it will usually lead to compensatory hyperplasia of the mammary glands, which will be manifested as pain when pressing on the breasts. 3. Breast fibroma: breast fibroma is a benign disease that occurs in young women, mainly caused by breast fibroblasts that are overly sensitive to estrogen, and also accompanied by lumps, usually accompanied by breast pressure pain. It is suggested that if the breasts are painful during the developmental period, it can be examined and treated in the breast surgery department of the hospital.