I had my appendix out a few months ago, if the pain hasn't gone away after 8 hours go to a hospital/doctor. (Hospital being the better idea, IMO.) Is the pain in your stomach, or in the lower-right abdomen?
On a side note, my surgeon did my appendix diagnosis something like this:
Him: "OK, lay down. Does this hurt?" *pokes me in the really painful spot.*
Me: *******!!!
Him: "OK then, we're going to remove your appendix then.
Nurse: "Shouldn't we give him a CT scan first?"
Him: "Well, in that area the only things that can hurt are the appendix or ovaries. I think we can rule out the ovaries thing."