Ay, nipple soreness can totally be a hormonal thing, lalo na if you're on Diane pills, a few of us moms noticed similar stuff when we were on hormonal contraceptives, and it usually gets better after your period or it's linked to your cycle. Since you're finishing your pills bukas, it might be PMS-related talaga, but if the soreness doesn't go away in a few days or gets worse, best check with your doctor just to be sure, okay? In the meantime, kung masakit talaga, avoid tight bras and hot water, and you can try some soft compress if needed.