During the developmental period of girls, the chest hurts when you touch it, most of them are physiological phenomenon; if the pain is serious, it may be caused by breast hyperplasia, trauma and other diseases. 1. Physiological phenomenon: girls enter puberty, due to changes in the level of hormones in the body, will lead to breast development, so there will be swelling of the mammary glands, touching pain, which is a normal phenomenon, most of them will recover on their own, generally do not need special treatment. Pay attention to wear underwear, choose loose and comfortable, reduce the pressure on the breast, you can also take local hot compresses and other methods to relieve the symptoms of swelling and pain. 2. Mammary gland hyperplasia: The high level of estrogen in the body during the developmental period of girls may also lead to mammary gland hyperplasia, which may cause congestion and edema of the mammary gland, resulting in the symptoms of pain when the breasts are touched during the developmental period of girls. Usually after the end of menstruation, the pain will be relieved on its own. 3. Trauma: traumatic factors such as extrusion of the mammary glands by external forces can also cause symptoms of chest pain. In addition, mastitis, cardiothoracic diseases, herpes zoster, breast cancer and other diseases may also produce similar symptoms, you should consult a doctor in a timely manner, to clarify the cause of the disease after treatment.