How possible is it to train yourself to ignore pain?

I have been trying to deal with the pains of reflux as best I can, but it is just too much. I was speed skating earlier today, and the pain from acid coming up my throat was so strong that my brain was telling me that I was about to pass out.

There are ways of training yourself to ignore pain. I have no experience in anything like this, but if anyone else does, could you tell me how possible it would be to do for reflux?