The most common symptom of breast cancer is a hard lump in the breast, which is rarely accompanied by pain. Breast cancer lumps are often irregular in shape, hard in texture and close to stone, and they are not smooth and have poor mobility and tend to adhere to the skin and surrounding tissues. Sometimes it is accompanied by enlargement of lymph nodes in the axilla on the same side. Breast pain in women is not likely to be caused by breast cancer, but is more commonly caused by breast enlargement, which is usually cyclical in nature and strongly associated with menstruation, usually manifesting as breast swelling and pinching pain about 1 week before the onset of menstruation. The pain will gradually decrease or even disappear completely after the end of menstruation. If you suspect breast enlargement or breast cancer, you can go to the hospital for an ultrasound screening of the breast, which is a very direct and simple method.