That being said, a significant portion of the pain is from giving birth on a hospital bed - or just lying flat in general. It is said (as a man, I have never given birth) that it is less painful, and therefore less in need of an epidural, if the birthing is done in a upright or crouching position. Like how an orangutan does it : http://youtu.be/JfVnFJDjUyQ?t=30s
The very idea of lying down for a birth dates back to the 18th century, when some French king wanted to see the birth of his heir. Of course men were not allowed in the birthing room, so he had to peek through a hole in the wall - or something like that. And the queen had to be in a position that allowed the king to see, so she was lying down facing so the king could see what was going on.
My wife had two pregnancies: one was 52 hours (with five hours of pushing!). The second was about 2 hours total.
Neither involved pitocin.
Baby was 9 lbs, 9 oz (4.3 kg).