If nipple pain occurs every month, consider that the cyclic pain is related to your period. Because the estrogen level in the body slowly increases before the start of the period, estrogen acting on the estrogen receptors in the breast tissue will lead to breast hyperplasia, which will also cause nipple pain, and at the end of the period the estrogen level in the body will drop and the breast and nipple pain will disappear, so there will be a phenomenon of nipple pain for a few days every month, which is related to the change in the hormone level in the body. If the nipple pain occurs periodically during the non-menstrual period, it is considered a breast lesion, when the breast has hyperplasia blood circulation will accelerate the non-menstrual period nipple pain, underwear does not fit squeeze is also possible. If this happens, it is recommended to check the fit of the underwear first, and if it does not fit, it is recommended to replace it. If it is not due to the underwear, it is recommended to go to the hospital for a mammogram to see if there is a disease such as breast enlargement.