Oh, I had this with DD
When she started sucking, it was like someone was driving red-hot needles through my boob, and it lasted for a good long while during each feed. MW was telling me it could be the latch (wasn't - she fed very well!), then she told me it could be thrush (again, it wasn't, but she put me through getting tested
).
Then, when she was ready to sign me over to the HV, she said (and it's still something which brings me out in a 



), 'why don't you try moving to formula then?' My DP said, when he heard how cavalier she had been about it, 'well, she doesn't care now, she's ticked her boxes about you BFing!'
So I started giving her one bottle a day, just for some relief (she was cluster feeding, too). After about 6 weeks or so, the pain started to diminish and by the time she was about 2 months old (I think, a while ago now, I was BFing like a pro!
So I guess what I'm saying is that you should stick with it if that is what you want, but don't let anyone tell you what is best for you. Only you know how painful it can be and only you know what is best for your family.

But the pain will probably go. I had a friend (who was on her third) tell me that 6 weeks is often how long it takes to get used to the whole malarkey. Seems like a lifetime but, as it's your second, you'll know it's not!