Breast swelling and pain may be caused by breast cancer, mastitis, breast hyperplasia and other diseases, commonly used drugs are aromatase inhibitors, antibiotics, anti-estrogenic drugs, etc., the use of drugs should follow the doctor’s instructions. 1. Breast cancer: Aromatase inhibitors such as letrozole can be used to treat estrogen receptor-positive breast cancer in all stages, benzene allergy is prohibited, adverse reactions include loss of appetite, nausea, vomiting, diarrhea and so on. 2. Mastitis: antibiotics such as penicillin can be used for mild and moderate infections caused by pathogens that are highly sensitive to penicillin. It is prohibited for those with a history of allergy to penicillins or procaine, and adverse reactions include various types of skin rashes, leukopenia, and so on. 3. Breast hyperplasia: anti-estrogenic drugs such as Tamoxifen and other drugs have a better inhibitory effect on breast hyperplasia, and can alleviate the symptoms of breast swelling and pain due to breast hyperplasia. The appearance of breast swelling and pain should be timely consultation, under the guidance of the doctor for treatment, so as not to miss the condition.