I have the same thing. it's really become a form of OCD for me, especially with my blood pressure. I have been to sooooo many specialists to rule everything out and of course all my tests come back normal! even when i think i "know" something is wrong. Now that i'm on medication my ocd about all that is starting to get better. But like you any little pain sets me off. I noticed i will sometimes find myself reading the other boards in this forum, then check symptoms and think i have whatever disease sickness i'm reading about.
Thats the one good thing about anxious people though! we go to the doctors so damn much that if we ever do have something wrong i'm sure will find it in plenty of time! I'm at that point now though where if anything else does come up i'm just going to ignore it, cause i'm sick of going to so many doctors and waiting weeks stressing over results.
Now whats really scary and gets me anxious, is to actually think of what i'm going to be like in the future if something DOES happen and i get some disease or sickness! I'm lucky cause it's always nothing, but just thinking about that freaks me out. I'd never be able to be happy again lol, cause every time i'm waiting for results i'm so nervous anxious, then when i find out i'm fine i feel like a million bucks! i can't imagine never getting that call that everything is ok and having something for the rest of my life