Our breasts are pretty dictated by hormones. If your hormones say so, you will have breast tenderness. Yay, right? I also find certain times in which I'm cold and have recently exercised and wearing a tight sports bra, that rubbing and such will cause me to be a bit like you describe too. I would not be concerned about this but at your next well check appointment, you can ask about it if it continues to happen.
Hi. How long has it been like that? Most likely it's hormonal. Talk to doctor. Maybe can adjust dosage. Are you sure your not pregnant?