There are two main possibilities for breast pain: first, cystic breast hyperplasia, which occurs in women of childbearing age between 30 and 50 years old and is associated with endocrine hormone disorders, the clinical manifestation of which is breast swelling and breast hyperplasia nodules that change with the menstrual cycle, and when the pain is obvious, you can get away with it, and the symptoms can be alleviated. The second is acute mastitis, which mostly occurs in breastfeeding women, is an acute suppurative infection of the breast, in the early stage of infection, there is only a pinprick pain in the breast accompanied by localized redness and swelling of the breast, when the infection spreads further, there will be a breast abscess and fluctuating lumps touched in the breast, which often requires surgical treatment. In case of acute lymphadenitis of the armpit or sebaceous cyst of the armpit with infection, tingling on the side of the breast under the armpit may occur when the pain is severe and affects the breast.