Get him checked for tongue tie, if he hasn't been checked already. And I don't mean just visually - someone needs to check with their finger. Even a partial posterior tongue tie can make it hard to bf; and having it snipped can make all the difference (or very little, depends).
Other than that, you probably just need to have the latch re-checked.
DS is 4 weeks old tomorrow and BF was going fine up untill last week. Obviously i had the initial pain as my nipples got used to it and he had a few days of bad latch but then we were flying it. Last week my nipples started to hurt again and he is making them go into a lipstick shape like he did at the beginning. i take him of and ty to get it right but i had to express fr a few day and bottle feed to give them a break or a few days as it was so sore it was making me cry. He is now refusing the bottle and only wants my boob but we just cant seem to get it right. I am going to a BF group on thursday but i need some help till then. i want to get him back on the boob full time asap.