The root causes of nipple pain are as follows: 1. Breast pain during pregnancy: The reason for breast pain after pregnancy is closely related to the large amount of estrogen, progesterone and prolactin secreted by placenta and villi, which leads to breast hyperplasia and breast enlargement, and finally to nipple pain. 2, breast proliferative breast pain: breast proliferative breast pain will be affected by menstruation, mood. This kind of breast pain is caused by metabolic disorder, accumulation of metabolic waste, qi stagnation and blood stasis in the body, which can be relieved by taking some drugs to promote blood circulation and regulate endocrine. 3, postpartum breast pain: postpartum breast pain is mostly mastitis, in addition to breast pain, there will be fever and local breast lumps. Breastfeeding should be carried out as soon as possible after delivery to avoid excessive accumulation of milk in the breast. 4, cancerous breast pain: when breast pain persists, the pain is fixed and radiated to the shoulder and back, and there is a sense of weight in the shoulder, there is a possibility of breast cancer, which must be highly valued and go to the hospital as soon as possible. 5, premenstrual breast pain: premenstrual breast pain is caused by the increase of estrogen level in the body, breast hyperplasia, cell enlargement, breast cell edema. This kind of breast pain generally does not need treatment. Pay attention to a light diet before menstruation. 6, breast pain: breast pain is manifested as dull pain, swelling pain or tingling, pain can radiate to armpits, shoulders and upper limbs. There was only tenderness during the examination, and there was no lump. Traditional Chinese medicine is the first choice for treatment, which has the functions of soothing the liver, benefiting qi, relieving depression, promoting blood circulation and removing blood stasis, and regulating endocrine. For normal girls, the 8-year-old areola begins to get bigger and darker. 9-year-old nipple development, 15- 17-year-old breast development to adult size. If a girl is average at 17 years old, it is morbid. The doctor of Changchun Dermatology and Urology Hospital reminds: The developing girl's nipple often hurts, which is the normal situation of growth and development. Pay attention to changing underwear frequently at ordinary times. If you have any problems, you should tell your mother in time. The situation is not serious.