Breast swelling and painful nipples when touched may be a physiological phenomenon caused by factors such as puberty, menstruation or changes in hormone levels during pregnancy and childbirth, or it may be a pathological phenomenon caused by mastitis, mastopexy and breast tumors, etc. The causes need to be clarified to avoid delaying treatment. I. Physiological causes: 1. puberty: the youthful development of estrogen secretion, may cause breast development when the breast swelling pain nipple pain when touched; 2. the influence of the menstrual cycle: ovulation or menstruation before the onset of high estrogen levels, can cause breast swelling pain nipple pain when touched; 3. maternity: at this time due to estrogen, progesterone and prolactin stimulation, breast duct development, may produce breast swelling pain nipple A touch of pain; 4, frequent stimulation: such as improperly dressed underwear to stimulate the breasts and nipples, frequent stimulation when couples have intercourse, etc., may cause breast swelling and painful nipples a touch of pain. Considering that the causes of breast swelling pain nipples ache when touched are complex, it is recommended to go to the hospital for further examination and treatment if necessary. Benign tumors, such as breast fibroids or breast cysts, can also cause painful pressure on the breasts and pull the nipples at the same time, causing pain when touched. The early symptoms of malignant tumors of the breast are not obvious, but with the development of the disease, symptoms such as breast swelling and pain, nipple invagination or overflow may appear, and at this time there may be pain when the nipple is touched.