I tend to agree with most of the posts here, and i was secretly pleased to see you have your mind set on vaginal birth. Good for you.
Pain tolerance has little to do with it, it's all about your labour. For me i think the great thing about the vaginal delivery (for me) was that once it was over, the pain was all gone. Even the stitches weren't that bad. I would definitely do it that way again if i can, so that means it can't be all that bad, aye!
Yep, it's painful, but as the other's said, it's constructive pain. And you can always just squeeze DH's hand a little bit tighter !!

Good luck, I hope you have the birth experience that you dream of.