Okay, it probably is just you becoming engorged with milk. If you ye the hot compresses and massage them while you pump and make sure that you are pumping ALOT, you'll be fine 😊 the beginning is tough but it gets so much better.
How old is she? In the beginning your milk supply is a lot heavier, are you pumping at all? Definitely make sure that you are just to keep from becoming engorged. Unfortunately it is pretty normal to experience some pain in the beginning especially if you're a FTM like I was, your nipples are super sensitive and not used to a baby nursing constantly. To help your milk come down easier, you can stand in a warm shower and let the water run over them, or use ice/ heat packs that they sell specifically for breastfeeding mothers. I also massaged every time I pumped to help my milk flow out.