First birth was back to back and went on for ages. It wasn't "pain" as much as feeling like being in an airport and kept being told the flight was delayed. YOu just want more than anything to get it over with. The room was very badly laid out so I couldn't get comfortable and didn't know where to put myself. That was the worst bit. Hopefully things are more enlightened now.
I think it was more like extreme exertion than pain. Like climbing a high stairway slightly faster than you'd like, uncomfortable or achey, rather than actual sharp or nasty pain. The actual pushing feels more like hard exercise tand because you know its the last lap - you are more distracted by thinking this is nearly over.
I think when you see people screaming, it's not so much because of the pain but because of the effort, and yelling (and swearing, sorry) or thrashing around really helps, at least that's how I saw it. Imagine you had a really big weight to lift and yelling helped you lift it. Or Tennis players yelling as they serve a very fast ball.
It does feel uncomfortable, and is occasionally painful, ( perhaps like back pain) but it is more that there are highs and lows of that. It's never unendurable and
There are breaks in between where you can rest a bit.
By the time it is approaching action stations you are not really thinking about "the pain" because its suddenly become more and more "busy" and you just want to get it all over with and are kind of distracted by that. My midwifes were very good helping with the breathing and that really really helps and also helps you feel more in control
I had gas and air which made no difference and asked for epi in the end mainly because I was exhausted but was told it's too late for that now as he was on his way.
Second births were much much shorter and were so busy.. No pain relief no gas and air, didn't really have time to think about it.
I do remember thinking at one point. If only I could have a nice glass of wine, I'd feel so much better - but alas that is not allowed.
Every birth is different. Don't let people frighten you. Take advice from the medical professionals around you and try to do all the breathing and stretches. Being relaxed makes everything easier. It is also absolutely true that once baby is out... "pain" is over and that's all you think about. Best of luck!