It's been about four years since I breastfed my son, but because of the great experience and success I had with it for him, I'll be breastfeeding my second baby I'm pregnant with now.
The only pain I remember was getting engorged when my milk came in two days after he was born, and I couldn't figure out how to get my stupid breast pump to work (word of the wise: don't buy a cheap breast pump). ;-)
I tried to feed him when I got engorged, but it took him about two weeks to learn how to latch on correctly. I had to use a nipple shield for two weeks so he could learn how to latch on and s uck properly, because from the day he was born, he was a biter/chewer.
The only other pain I *vividly* remember was after he grew a few teeth and then that biting and chewing behavior came back full-force in the prime of his teething, which was around 8 months old.
That's when I decided to wean him, lol.
Actually, he more or less weaned himself because he was more interested in chewing things up.
I was told the same thing by other women, how it's soooo painful. For me, it did not hurt at all. Yes, initially you'll experience some cracking but only for a few days. I recommend finding a good cream to use - I used the brand Lansinoh and it relieved or prevented any pain and worked really well. It is true though, it will hurt if the baby isn't latching on properly. Taking a class is probably good. I didn't, but the lactation consultants in the hospital visited me both days I was in the hospital and gave me some very helpful tips. They were also available for me when I called with any questions.
I think the latching on issue is what causes the most pain. You may also experience engorging once your milk comes in. They way to relieve that is to feed the baby (or pump). Cold cloth's and warm showers also help. Do not bind your chest though - that's a common misconception (as to what will help engorging).
Do not get discouraged. Every person tolerates pain differently.
In my case it hurt for about 10 days. Both baby and Mom need to learn how to work together on the breastfeeding relationship (both need a little practice to get the technique right) and it wont necessarily happen straight away.
Once the nipples have calloused a little (in my case ~ 10 days) and baby latches on correctly it wont hurt but yes, it can sting a little at first. The pain wasnt that bad though and the way I viewed it, if I could get through pregnancy and childbirth then I could get through nursing too!
There are so many benefits to nursing and I am glad I stuck it out.