I have not given birth yet, but acute appendicitis/emergency appendectomy at 23 weeks pregnant was the worst pain I have experienced. During my recovery the labor/delivery nurses who would come to my room to check Baby's heartrate with the doppler would joke that labor pains would seem easy compared to the pain of appendicitis. We'll see! I also went through my recovery and healing without taking pain meds out of concern for LO. That sucked but I was willing if it was better for him.
As others have said though, there are different kinds of pain. Sitting crouched in the emergency room with a nearly burst appendix, waiting for an hour before I was seen was a horrible kind of pain - bewildering, unrelenting, wondering what was wrong with me and how would they be able to fix this. It was a strangely helpless feeling.
With childbirth, at least you know why you are hurting, and that the reward for all your effort is a sweet little baby