It's related to hypersensitivity/sensory processing issue, which is common with AS/ASD (or so I've read). My psych wants me to see a neurologist about other things, but I will certainly bring it up. It is bothersome, as I just don't like the way it feels being touched certain places. It really bothers me, particularly my stomach and head. I get really hot and itchy/sweaty, and it feels ... Painful is the closest word but it's not the right word. I honestly don't think the proper adjective exists since I have come to realize most people don't feel like I do in the same circumstances.
As to whether I am "comfortable" being touched... That depends on the context. There are a couple of issues here. I want to hug my wife and have found enjoyable ways to do it avoiding sensitive areas. Sometimes things go haywire, though, and I can't even when I want to.
I don't usually want to hug strangers or people with whom I am not close, and that is as much more a "want" or "anxiety" than pain or quasi-pain. I think most (not all) of us here on the spectrum have some reservations about when we are comfortable getting close and to who. Some of us, and I am not sure how many, actually are in physical discomfort or pain in these situations though, not just psychological.