Agoraphobia (from Greek ἀγορά, "marketplace"; and φόβος/φοβία, -phobia) is an anxiety disorder characterized by anxiety in situations where it is perceived to be difficult or embarrassing to escape.
agoraphobia n : a morbid fear of open spaces (as fear of being caught alone in some public place)
Social Phobia is distinguished by an irrational fear of public humiliation or embarrassment. It is one of several phobia disorders, which are all typified by excessive, specific, and consistent fear and avoidance of an object, activity, or situation.
social phobia n : any phobia (other than agoraphobia) associated with situations in which you are subject to criticism by others (as fear of eating in public or public speaking etc)