Wait a minute... I think we may be missing something simple. Is he saying it hurts for you to touch it after he comes? Is that what the context is, he tells you "<hiss> don't touch it!"? Many guys, especially when they're young, have a hypersensitive penis after they come. You can't stand for it to be touched for a couple minutes, but it doesn't hurt, as in there's damage, it just hurts to be touched. Stimulation that used to feel good is now unbearable because the whole penis is a raw nerve in the aftermath of the orgasm. This is normal, if that's what's happening.
hes never told me not to touch it after he cums even wen he came in my mouth i just let him finish cuming to i can clean it upp n den wen i took it outta my mouth he just started to complain it hurted agan he just says it hurts wen he cum...in general he dont give himself a hand too often because of it...i think...idk if hes lyin to me
Alright. Well, he needs to see a doctor, then. I don't know any guys who don't hate to go to the doctor, but usually when something's wrong with their dick they'll make an exception. I think you're kind of strange, too, for continuing to have sex with him when there's something unknown going on there. It's possible he's got something contagious. And you say he's not your only lover. You did say you get tested often, but some things take awhile to show up on tests, and the fact that you get tested isn't a really awesome reason to take risks. An ounce of prevention, and all that...