The breasts of adult women are two hemispherical organs of sexual characteristics, located on the superficial surface of the pectoralis major muscle, raised above the skin, and the whole breast gland is connected by Cooper’s ligament up and down. So when girls run, due to the violent shock of the body when running, it is easy to lead to pulling pain in the mammary glands, especially women with larger mammary glands, the pain symptoms are more obvious. You need to choose more comfortable sports underwear that can slow down the symptoms of pain. If the usual amount of exercise is relatively small, and suddenly the amount of running is relatively large, it is easy to lead to lactic acid accumulation, can also appear the symptoms of chest pain. So usually try to increase the amount of exercise gradually to reduce the discomfort of the breast symptoms. If you suffer from cystic hyperplasia of the breast, you can also experience chest pain. In either case, the presence of persistent pain is recommended to promptly visit the hospital for examination.