Breast pain when lifting the arm is associated with breast trauma, cystic hyperplasia of the breast, acute mastitis, and breast cancer. Under normal circumstances, there is no pain in the breast when lifting the arm. When the pain is caused by trauma to the breast, under the impact of external force, there will be congestion, edema and acute inflammatory changes in the breast area, which will cause breast pain at this time. Excluding trauma, cystic hyperplasia can be considered as a manifestation of breast enlargement. Breast enlargement easily occurs in women of childbearing age, and when the hormone level continues to increase before menstruation, it will lead to nodule-like changes in the breast, and the pain will gradually increase before menstruation, especially when lifting the arm and dressing. In breastfeeding women, due to lack of attention to local cleanliness and hygiene, bacterial infection in the nipple area may lead to acute mastitis, which may be characterized by redness, swelling, heat and pain, and may cause difficulty in lifting. Finally, breast cancer can also be considered. The lump will grow faster and metastasize to the axillary lymph nodes during the development stage, which will lead to enlarged and painful axillary lymph nodes and affect the movement of the upper limbs.