All I’m going to say is this (and this was my experience with DD1 and bear in mind I’m on antibiotics for mastitis that was nipped in the bud on Thursday last week)
Sure baby latching on will hurt; it’s like having a tiny terrapin on you but your nips apparently toughen after about 3 weeks.
Internal breast pain, swelling, heat, “crackle” and soreness at rest or gentle touch indicates either
a) infection and/or
b) blockage
I’m not an expert but learned from bitter, bitter experience back in 2016 when a heap of bfing “supporters” would not listen to the pain I was in.
If you are in pain @swiftfox and you’ve tried your GP, HV, midwife etc the last point of call I’d suggest is La Leche League. Apparently they send folk out to help folks in distress and are no wallflowers when it comes to telling folk what’s wrong, whether it’s a maternal issue (mastitis) or infant (posterior tongue tie, bad latch etc).
Once again, BFing can mentally break some folk and IMVHO it is not worth it but knowing the emotions around it I’d encourage anyone to exhaust all support possible.
Good luck and I’ll shut up for now xx