What Causes Nipple Soreness After Ovulation With Irregular Periods?

hi doctor ,IM 20 YRS OLD ,MARRIED WITH IRREGULAR PERIODS.BUT NOW THAT I'VE LOST WEIGHT ,IT HAS BEEN BETTER. RECENTLY STARTED EXPERIENCING SORE NIPPLE AFTER OVULATION. AND STILL WAITING FOR MY PERIOD. NOW I'VE HAD THAT EXPERIENCED BEFORE WHEN I WAS PREGNANT.WHAT COULD IT BE...