There are many reasons for the vague pain on one side of the breast. Consider the pain caused by fire, inflammation, or it may be caused by breast enlargement or the formation of a lump. You should go to the hospital for an ultrasound examination to see if there are any breast nodules or other diseases. It is normal for women to have a slight stinging pain in their breasts when their periods come or after their periods are over. You can wear loose, breathable clothes, get enough sleep, and eat less spicy, stimulating food to reduce the symptoms. Gently press the pressure, do not overdo it, pay attention to rest, do not work hard, stay up late, relax, do not be depressed, eat less food containing high estrogen, such as soy, soy milk, black rice, etc.