So I'm 7 weeks into the whole breastfeeding ordeal and we've gotten past thrush and a humdinger of a…

So I'm 7 weeks into the whole breastfeeding ordeal and we've gotten past thrush and a humdinger of a cracked nipple, and now we've hit a bit of a brick wall.

After feeding for about 10, maybe 15 mins he just starts screaming. I've winded him, changed his nappy, checked for more thrush, and nothing is helping. He just screams when I try to relatch him on.. and then I try the other side and he is fine for another 10,15 mins and then the same thing happens.

Anyone any ideas on what's going on?