Pain at the lower edge of the breast is most commonly caused by breast diseases, but it may also be caused by heart or liver and gallbladder diseases, and further examination is recommended. 1. Breast diseases: Breast hyperplasia, breast cancer and other diseases can cause pain in the breast, mainly caused by changes in human hormone levels, it is recommended to actively carry out the six tests of female hormones and breast ultrasound and other clear diagnosis. 2. Heart disease: if the pain appears at the lower edge of the left breast, the possibility of heart attack cannot be excluded, such as angina pectoris, myocardial infarction, myocardial ischemia, etc. It is recommended to improve the electrocardiogram, cardiac infarction and other tests. 3. Liver and gallbladder diseases: if the right side of the lower edge of the breast pain, may be cholecystitis, hepatitis, cirrhosis and other diseases, need to improve the ultrasound and other tests to clarify. At the same time, the lower edge of the breast pain need to pay attention to whether it is a skin disease, gastric disease, rib disease, etc., need to be identified accordingly; It is recommended that patients go to regular hospitals in time, improve the examination to clarify the cause of the disease, and use reasonable medication under the guidance of the doctor, do not blindly use their own medication.