Unilateral paroxysmal stabbing pain at the root of the breast may be due to breast diseases such as breast cysts, mastitis, breast hyperplasia, etc., and can also be due to radiating pain in the chest wall and heart. 1. Breast diseases: (1) Breast cysts: some cases may show pain, which may be accompanied by localized lumps, and a few may be accompanied by nipple discharge. (2) Mastitis: pain may appear, accompanied by localized skin redness, swelling and fever. (3) Breast hyperplasia: pain is often the first symptom, and the pain can be periodic, and the lump can be touched. 2. Radiating pain caused by chest wall diseases: Radiating pain at the root of the breast may occur in diseases including sternitis, nerves around the sternum, strained muscles such as the serratus anterior, and so on. 3. Radiating pain due to heart disease: The common cause is angina pectoris, which may radiate to the intercostal space, back and other places, but usually combined with dyspnea, fainting and other manifestations. When breast pain occurs, it is recommended to go to the hospital in time.