Re: hurting again???
I'd say pay special attention to how she's latched on...not just at the beginning but all the way through the feed. As she grows and you both get more confident, it's easy to get a little lazy about latching. When DJ first started nursing, I had a lot of pain and soreness so I went to see an LC. She watched me latch him on and said it was textbook so she wasn't sure what the problem was. We chatted a little as he continued to nurse and all of a sudden she noticed...as the feeding went on, I'd slouch a little and he'd slip down into a more comfortable position and the latch at the end of the feed was VERy different from the beginning. She also showed me a couple of other "tricks" that made a huge difference for us.
Bottom line, it shouldn't be painful...maybe not always extremely comfortable...but never painful. So if it hurts, get help before it gets out of hand.