There are many causes of breast pain, such as cyclical breast pain, which occurs a few days before menstruation and is generally thought to be caused by an increase in blood supply to the breast during this period, causing lumps and pain. Another example is breast infection, which can cause acute mastitis or breast abscess. In addition to pain, it is often accompanied by localized redness, swelling and burning sensation, which can sometimes be controlled by antibiotics alone, and sometimes requires surgical incision to drain the pus before the pain disappears. In addition, breast cysts can also cause pain. This occurs after breastfeeding has stopped, because the milk ducts under the areola are blocked and dilated, and the inside is full of milk and shed epidermal cells, when you touch the breast, you feel the enlarged milk ducts and feel pain. Other traumas, such as postpartum milk gain, breastfeeding or excessive sucking during sex, will also naturally cause pain. Finally, breast tumors can also cause pain and are the most important to be aware of. In fact, breast cancer itself rarely causes pain. According to some statistics, only about 5 of breast cancer patients have breast pain as their first symptom. According to clinical experience, there is one painful sensation that requires special attention, which is an intermittent, sharp stabbing pain from inside the breast, but the painful sensation does not tract to the external part of the breast. When there is such pain, it should be carefully examined for lumps so that a biopsy can be done.