Uy mama, totally normal yan sa pregnancy, a lot of us experience it, especially around that stage! The hormones are really doing a number on our breasts, and as baby grows, the pressure and changes make them extra sensitive and sore talaga. That said, since you're worried and it's really sobrang sakit, better check with your OB just to make sure everything's okay, sometimes they can recommend safe ways to ease the discomfort like cold compresses or adjusting your bra fit. My friend swears her pain lessened when she switched to a softer, pregnancy-specific bra, kaya subukan din yan in the meantime!