Did you ever try removing yourself from social situations? I like to pretend I'm acting, which is easier than thinking I'm really talking to real people, which makes it easier. Sometimes I pretend my body is a giant machine, and I'm just a little guy inside operating the controls, like the alien from Men in Black who lived inside the human-shaped robot :
The picture only makes sense if you saw the movie. If not, think about Voltron. Or whatever the modern version of voltron is for the younger kids these days.
This shouldn't a permanent solution, but a crutch. It's a way to deal with being around other people until you become more comfortable with other people. Get into your character and go out and try interacting with people. Even if you really don't want to, try just being outside around them, because it's the only way to get good at it.