"A previous negative social experience can be a trigger to social phobia.[33][34] perhaps particularly for individuals high in 'interpersonal sensitivity'. For around half of those diagnosed with social anxiety disorder, a specific traumatic or humiliating social event appears to be associated with the onset or worsening of the disorder;[35] this kind of event appears to be particularly related to specific (performance) social phobia, for example regarding public speaking (Stemberg et al., 1995). As well as direct experiences, observing or hearing about the socially negative experiences of others (e.g. a faux pas committed by someone), or verbal warnings of social problems and dangers, may also make the development of a social anxiety disorder more likely.[36] Social anxiety disorder may be caused by the longer-term effects of not fitting in, or being bullied, rejected or ignored (Beidel and Turner, 1998). Shy adolescents or avoidant adults have emphasised unpleasant experiences with peers[37] or childhood bullying or harassment (Gilmartin, 1987). In one study, popularity was found to be negatively correlated with social anxiety, and children who were neglected by their peers reported higher social anxiety and fear of negative evaluation than other categories of children.[38] Socially phobic children appear less likely to receive positive reactions from peers[39] and anxious or inhibited children may isolate themselves.[40]"
The above is from Wikipedia. Maybe you've done this already, but in case you haven't: reading the psychological criteria for Social Anxiety Disorder, Social Phobia Disorder or Avoidant Personality Disorder should give you some notion as to whether you are afflicted by these mental disorders or if if it's something else.
