To re-visit this idea, I think there must be something going on to facilitate a birth that is pain-free. Why couldn't changes of positions, support and encouragement, and a mindset that approaches labor and birth as normal be a part of creating the pain-free experience?
The contractions themselves also hurt. They hurt like the worst menstrual cramps I'd ever had. I heard them described that way later, but I'd never heard them described that way at the time. They felt just like cramps. So did all three of my miscarriages. I have to think that the pain does have a physical/physiological basis when it so closely mimicked other pain I'd felt. I really can't say what role expectations played in any of it. I had no expectation of painful periods, as I'd been menstruating for almost two years before I had one that hurt, and the painful ones never were predictable. I certainly didn't anticipate my miscarriages - just pain that came out of nowhere at 12 weeks gestation. Yet, that pain was just like my labour pains.
I do think pain management is tremendously important. The role of changing positions is hardly going to revolutionary information on this board, but I know how important it is. When I went in for my scheduled section with ds2, I'd been in labour since the night before. The contractions hurt - more than I'd remember, actually - but they weren't terrible. I was riding them out fairly easily...walking around, mostly. When I got to the hospital, they put me on a bed to check dilation. When the next contraction hit, I was ready to claw out someone's eyes if it would make the pain go away. I honestly can't imagine what it feels like to go through an entire labour like that! It was brutal...so I definitely feel that it's essential to educate women (and doctors!) about alternative methods of coping with pain (changing positions, warm water, counter pressure, etc.).