I think there are a few books that help with social anxiety. Sometimes it depends on how open minded you are to the methods though. For example, Echart Tolle's, A New Earth discusses how suppressed negative experiences are constantly triggered in your daily life and he discusses a method on how to handle this "pain body" as he calls it. It focuses on accepting those negative feelings instead of resisting them.
I've tried many methods for overcoming social anxiety and building social confidence in myself and other people I've tried to help with the same problems. You can find some great methods in the book: Social Confidence Mastery.