I did this and still do this with Max!! It was just how he would naturally latch himself in the early days, and I got TERRIBLE headaches after he was born and couldn't sit up without getting sick. Laying back seemed comfortable for both of us. I did have some issues with cracked nipples, and i don't know if that made it better or not, but it just felt more natural than to be sitting up kind of all hunched up to me. If nothing else, it'll help you feel more relaxed
I hope it's working for you and it keeps getting less painful.