I'm not sure how to frame this post, or what to call it. I don't know how loneliness feels to others on the spectrum, or to anyone else, for that matter. It's a very private feeling that is hard to describe. That's why I can only speak for myself. I don't know that my loneliness is a side effect of Asperger's. I think it is, but I don't know for sure how others experience it, if they do at all.
When I was a teen I remember having this conversation with a 'friend' where she said "You can be in a room full of people, and still be lonely". I replied that I didn't think that made sense. How can one be alone, and with others at the same time. She maintained that there was a big difference between alone and lonely.