I am pretty sure we just had thrush. Supposedly, the white will NOT rub off with a moist qtip or washcloth if it is thrush. Do your nipples itch when not nursing? Are they red and shiney? I am not an expert at all, but I just went trhough it and these are the things that come to mind.
We used gentian violet for 7 nights and it made the pain go away right away. I saw mixed reviews and was a bit worried about using it. I would do your own research on it first. There is also the jay gordon method:
If you do have thrush, you need to wash everything in HOT water (nursing pads, shirts that get milk, burp cloths, baby clothes). Sunning your breasts is supposed to help too.
Hopefully you dont have it.