Physiological breast swelling has a variety of causes, there are normal physiological phenomena, but also may be related to some abnormalities, mostly caused by hormonal changes in the body, more common are the following six: 1, adolescent breast swelling: adolescent breast swelling is between 12-18 years old, varies from person to person, generally secondary sex characteristics development, estrogen level changes caused, can be related to genetics, nutrition level. During the development period, pay attention to a reasonable diet and wear a suitable bra to prevent pressure and constraint on the breasts to ensure the healthy development of the breasts; 2. Premenstrual breast pain: with a cycle, before the onset of menstruation, estrogen levels increase, breast tissue edema can cause swelling and pain. Generally, as the period passes, the symptoms will gradually disappear. Need to pay attention to period warmth, do not strenuous exercise; 3, breast pain after sex: may be related to sexual disharmony, excessive sex life. Both parties need to communicate well, improve lifestyle and have a harmonious sex life; 4, breast swelling and pain during pregnancy: placental villi secrete a lot of estrogen, progesterone and prolactin, which can cause breast enlargement and enlargement, accompanied by swelling and pain, which can last throughout pregnancy in severe cases without treatment, and the symptoms can generally disappear gradually after lactation; 5, postpartum breast swelling and pain: residual milk, lymphatic retention in the breast, and breast 5. Postpartum breast tenderness: residual milk, lymphatic retention in the breast, and poor ducts lead to breast tenderness. The mother breastfeeds as early as possible, using a breast pump to suck out the milk and keep the milk ducts open; 6, breast pain after abortion: due to the sudden interruption of pregnancy, the body’s hormone level drops rapidly, the development of the breast suddenly stops growing, causing breast pain, as the body recovers, the symptoms will disappear. Attention should be paid to the care of breast swelling and pain when it occurs, do not press the chest often, wear comfortable, loose underwear, and try to choose cotton underwear with good breathability. Do not rub your breasts with violence when washing them, and try to avoid using chemicals for cleaning. Breast pain is not only limited to physiological pain, but may also be pathological, so learn to self-examine your breasts and seek medical attention for any abnormalities and discomfort.