There is something called the fear-pain-tension cycle that is probably the cause of a lot of pain in birthing. It is a viscious cycle - first you feel a sensation that startles or frightens you and you feel the sensation (sometimes after a small delay) as pain. Your first reaction is to fight against this sensation, to keep it from happening again. So you tense up. The tension adds to your fear, which perpetuates the pain.
A great example is a headache - when I get a headache, I subconsciously tense up my shoulder and neck muscles. This in turn makes the headache worse. If I catch it early enough, I can consciously release the tension and minimize or eliminate the headache. If not, it is a downward spiral.
Similar theory with childbirth. The first contraction hits - you remember pain from a previous birth, or the horror stories that everyone loves to share. Maybe you are scared that you aren't ready, you doubt if you are capable. Maybe you are not at 38 weeks, or maybe your DP is out of town or at work. Maybe the contraction is just way more intense then you thought it would be. You involuntarily tense up to "stop" the process, make the feeling go away. Once you tense up, you are fighting against your body and it HURTS!
This is not "all in your mind" it is real pain!
So there are programs, like HypnoBabies, that base the whole program on releasing the fear and becoming totally relaxed to break the fear-pain-tension cycle. If you've ever read Ina May's Guide to Childbirth, she talks about how they create a whole community that removes the fear from childbirth. She even talks about Orgasmic birth.
Other programs, like the Bradley method, teach you to expect the pain and work through it. So of course you do feel pain, but they give you tools to deal with it.
This fear-pain-tension cycle theory is not the definitive answer to pain in childbirth. It does not address pain caused by positional issues with baby, for example. There are some real, valid reasons why you might feel pain, even if you break that cycle and release all your fear.
To answer your initial question - yes, I had a pain-free childbirth. The worst I would describe it was mild discomfort during pushing (it happened realy fast and I tore slightly). I used HypnoBabies as my tool to get there.