There are many causes of breast lump 17mmx7.3mm with pain, cystic hyperplasia of the breast, fibroadenoma of the breast, breast cancer, breast tuberculosis and other diseases may occur. 1. Breast cystic hyperplasia: it is a common benign disease in women, which usually occurs with the appearance of the menstrual cycle and decreases after menstruation. Clinically, it manifests as swelling and pain in one side or both sides of the breasts, breast lumps, etc. Some patients have cyclicity, and in serious cases, they have pain throughout the menstrual cycle. 2. Breast fibroadenoma: It is the most common benign tumor of breast. It occurs in the upper outer quadrant of the breast and clinically manifests as a lump in the breast, which is mostly painless, but can be painful. Generally, the lump grows slowly, is hard and easy to push. 3. Breast cancer: it is the more common malignant tumor of breast, which is manifested as a single painless breast lump in the early stage, but some patients may have pain. The lump is hard, not easy to push, and grows rapidly. 4. Breast tuberculosis: this disease is less common, often secondary to tuberculosis, clinically manifested as breast lumps, pain is more obvious. Therefore, the breast lump 17mmx7.3mm with pain, it is recommended to go to the hospital as soon as possible to get a clear diagnosis, standardized treatment under the guidance of the doctor.