The causes of breast soreness are mainly divided into physiological and pathological factors. Before or during menstruation, women may experience breast soreness due to elevated hormone levels in the body. After strenuous exercise, breast soreness may also occur due to the accumulation of lactic acid in the body, which can be relieved by applying heat to the affected area. If we exclude physiological causes of breast soreness, we need to consider diseases, and we need to perform breast ultrasound examination to determine whether there are breast hyperplasia, breast cancer and other diseases. Some serious diseases of the chest can also cause breast soreness, such as pleural effusion, lung tumor, pleurisy, etc. The appearance of breast soreness must not be neglected and should be examined in time to avoid missing the best treatment period for the disease.