The pain in the breast is often caused by the following reasons: 1. Breast enlargement: This is a common female disease, caused by abnormal levels of estrogen and progesterone secretion in the body, which can be clarified by going to the hospital for general surgery or breast surgery. 2.Mass in the breast: it may be benign masses, such as fibroids, or malignant masses, such as breast cancer, so you need to go to the hospital for relevant examinations, such as ultrasound, CT, MRI, mammogram, etc. If necessary, you need to perform a puncture biopsy or excisional biopsy of the mass to clarify the nature.