I know that I have experienced it before, because I remember experiencing it and I assume that my memories are valid.
OK, this is important. As I was trying to get at before, even if your memories aren't valid, you should still know what pain is. Because even if you feel like you have memories of pain, then you do. They may not be memories of actual events, but presently, right now, as you're reading this, you should have a clear mental "picture" (for lack of a better word) of what it is, regardless of whether or not it was triggered by an actual physical event. I would expect that you would know with absolute certainty what it is. Correct?
I once had a load of boiling water accidentally poured on me. I came to understand entirely new horizons in pain that day....
Wow, so you're, like, a pain pioneer!
"Absolute certainty"? That's probably stronger than I can sign up for. How about this - I know it with at least as much certainty as I know anything else. I am as certain of this as I possibly can be. Hopefully you can still get where you want to go with that...
Wow, so you're, like, a pain pioneer!
Nah. I have little doubt that there is much territory in the land of pain where others have been but I have not. And that I have no particular desire to explore - the trouble with pain is that it hurts. It wouldn't be so bad if it didn't ;)