Yes, you can receive SSI, or disability benefits, for social phobia, also known as social anxiety disorder. When you have severe social phobia, then you are not able to be in crowds of people, or groups of people. If you have severe social phobia, then you have difficulty leaving your home as you avoid social situations. With being homebound due to severe social anxiety, then your functioning suffers, as you are not able to go to work or school, you are not able to go grocery shopping, you are not able to see your doctors, and you are not able to see you friends. You self-care may suffer, as you are not able to go to the grocery store or the pharmacy, as even the thought of interacting with people keeps you from obtaining the things you need to live.
For more information on how social phobia develops, and what you can do to treat it, please watch the following video: