Latching issues, sore breast and nipples

Baby chomps more then actually sucking, doc said its normal and I can pump between trying to latch so I know he's getting enough to eat. My problem is that my nipples hurt so bad from him chomping and not latching correct. He was born early Monday morning and on Monday night, and Tuesday night he was on my breast none stop so they thought it was cluster feeding at first. Now we are home and I don't know how to relieve the pain. When trying to feed him I tense up and want to cry because it hurts so bad, and I know he can sense that and it makes it more difficult. I don't have a pump yet and just need some input on how to ease the pain until we have breastfeeding down.