Breast swelling and pain may be caused by high estrogen level, cystic hyperplasia of the breast, acute mastitis, breast cancer, etc., which need to be adjusted by medication or surgery for the cause of the disease. 1. High estrogen level: Estrogen level rises during pregnancy, puberty, premenstrual period, etc. Estrogen promotes the proliferation of breast ducts, which may cause physiological breast swelling and pain. It is necessary to have reasonable rest, keep your mood happy, avoid emotional excitement, and eat more fruits and vegetables to supplement the nutritional regimen. 2. Breast cystic hyperplasia: Breast cystic hyperplasia is caused by the proliferation of breast lobules and ducts, which may cause breast swelling and pain. You need to keep your body and mind happy, and you can apply anti-estrogen drugs such as ethinyl estradiol, tamoxifen and danazol to improve your health. 3. Acute mastitis: Breastfeeding women may have excessive milk secretion leading to blockage of the ducts of the mammary glands and bacterial infections resulting in acute mastitis, which can lead to breast swelling and pain. You need to keep your breasts, especially the nipple areola, clean and as soon as possible to drain the milk, you can apply tetracycline, metronidazole, levofloxacin and other antibacterial drugs to regulate. 4. Breast cancer: malignant lesions of breast tissue cause breast occupancy and necrosis of normal breast tissue, so the breast may be swollen and painful. Surgery with radiotherapy and endocrine therapy is needed. In addition, breast fibroma, breast trauma and other reasons may also appear breast swelling and pain, we should consult a doctor in time to clarify the cause of the disease, under the guidance of the doctor treatment.