Breast swelling and pain before menstruation is mainly caused by hormonal fluctuations in the body’s secretion before menstruation. Before menstruation, breast fibers increase, lymphocytes infiltrate, and the breasts enlarge, so many women will feel the swelling and discomfort. If this swelling and discomfort occurs just before menstruation and decreases or disappears after menstruation, it is likely to be the cause of breast enlargement. Hormonal fluctuations in the body occur before menstruation, so many people experience a variety of discomforts before menstruation, a symptom known as PMS. The manifestations of PMS are varied and can include headache, breast tenderness, dizziness, facial limb edema, constipation, anxiety, depression, poor concentration, memory loss, and if the condition is mild, no treatment is necessary, but if the symptoms are more severe, counseling and medication are needed.