It’s one thing to be shy, but social phobia takes this to way beyond the next level.
Some kids may be so worried about being with their peers that they will avoid them by sitting alone at lunch time. Or not even answer the phone if someone calls. The perceived advantage of this is that it protects them! If an individual won’t go up and talk with certain kids, then they can’t say or do the wrong thing, and thus they can avoid feeling embarrassed or being rejected.
As it happens, this only makes the social phobia worse, reinforcing the thought that the person can’t do this.
As long as individuals are motivated, and want to change, a combination of medical hypnosis and cognitive behavioral strategies are helpful for this problem.