It's not that labor is worse than any pain you've ever felt in your whole life, it's just that it is different. Realizing how childbirth pain differs is what gets the experienced woman through labor in a much less painful way than a novice. It started out severe and was unrelenting no matter what you did. It just wouldn't go away. You would have given anything for a few minutes of relief.
Childbirth pain is different.
It's not unrelenting. There are blissful pauses between the pains, and the pauses may last a lot longer than the pains, at least early in labor. Put the pain in perspective. Each one is only 60 to 90 seconds long. You know that within a minute or more another pain is going to come.