I have been experiencing some pain in the nipple of my left breast only. I don't think that it is PMS symptoms because I have been on BC for 2 years and never experienced breast pains. I also do not think I am pregnant even though my period was irreguler this past time. Is there anything besides PMS and pregnancy that can cause breasts, to be sore?? The breast also looks fine and looks like the other one, it is just sore.

Thank You