I've given birth to four beautiful, healthy babies, all without the use of any sort of pain medication. They were all over 7 lbs with the second child weighing over 10 lbs at birth. I used self hypnosis techniques during every labor, got lots of exercise during every pregnancy, and even gave birth to the last child in a standing position (in the hospital). The hospitals generally don't like that, they prefer to keep their patients laying down and hooked to moniters, which does greatly increase the amount of pain that you can experience. Every one of my births hurt like nothing I could ever describe. I will never forget that pain.
I think, though, that the experience of birth, if it had been just an easy, non traumatic thing, maybe would not have bonded me to those babies so much. After all, I went through a personal hell to bring those little beings into the world, nothing could (or will!) stop me from enduring anything for them now.