Why does my right side breast hurt?

J
I've been pumping and breastfeeding less and using a supplementation since I'm alone right now and can't find the time. My right breast hurts very bad but only on the side. It's not hard; I thought maybe encouraged but after I pump it doesn't go away. Does it hurt when you dry up? I hope that's not the case but I'm just worried about infections. Any suggestions as to what this is?