Right breast swelling and pain together with right arm pain may be related to breast hyperplasia, mastitis and breast tumor. 1. Breast hyperplasia: The main feature of breast hyperplasia is cyclic breast pain. At first, it is diffuse swelling and pain, and the tenderness is obvious in the upper and middle parts of the breasts, and the pain increases before menstruation every month, and decreases or disappears after menstruation. In severe cases, there is persistent pain before and after menstruation, sometimes radiating to the armpits, shoulders and back, upper limbs and other places. 2. Mastitis: Acute mastitis during breastfeeding, breakage in the nipple area, bacterial invasion will form acute inflammation of the breast, inflammation of the right breast, there may be reactive hyperplasia of the right axillary lymph nodes, right breast pain and right arm pain. 3. Breast tumor: the enlargement of the lump in the breast will cause chest pain, and the serious symptoms will affect the upper limbs, which is considered to be due to malignant tumor of the breast, the tumor will gradually increase in size, and will metastasize to the lymph nodes on the same side, and the enlarged lymph nodes will lead to the restriction of the activities of the upper limbs and cause pain. In addition, right breast pain and right arm pain may be caused by different independent diseases, it is recommended to consult the hospital, standardized examination and treatment.