Welcome to PC.

Social anxiety and AVpD are related but have differences. It takes some time to separate the two. AVpD is more like social anxiety or shyness plus perceptions of inferiority and incompetency, exaggerated avoidance of risk, among other things.

Here's a link to a good overview of AvPD: Avoidant personality disorder - Wikipedia, the free encyclopedia
and a closely related disorder called Hikikomori, in Japan (also noticed in the Western world): Hikikomori - Wikipedia, the free encyclopedia
and finally Social Anxiety: Social anxiety - Wikipedia, the free encyclopedia