I could be off in my understanding of it, but I think it’s more like dissociating your ‘self’ from the pain more than actually getting rid of it (an intentional, mindful dissociation- not an unconscious one), so you can still notice it- but you’re disciplining your mind so that you can choose not to focus on it, you can choose not to let it distract you. That’s what separates it from chemical analgesics- which actually block the pain itself so you don’t have to pay any attention whatsoever.
Yes. I've done this myself many times when dealing with the pain of RA. I've also done this for childbirth. The drawbacks to this are that sometimes the pain reaches a level where I can't dissociate from it any longer. When it gets to that point, it's usually very, very bad and I know the only thing that will work at this point is some sort of chemical analgesic...immediately.