If I've understood you in the right way, you think that there might be different kinds of anxiety in sogial situations:
- when you actually want to participate
- or when you actually don't want to, but feel obliged to participate
Is this right?
I also think that it's important two distinguish these two kinds of situations. In the second kind, when you feel obliged, it might be even harder to socialize because you don't have enough motivation. I know this problem: I (probably) don't have an ASD, but I'm quite withdrawn and like to be on my own, while my friends often want to interact with me - so I have to get myself to talk to them so that they won't feel neglected. The only helpful things I know are to think about how happy the other person will be to have a conversation with you and to talk about somathing or do something together that both can enjoy (which can be quite hard).
Well, these are just my thoughts. I hope I really understood your question and my answer can help you a little.