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; this kind of event appears to be particularly related to specific 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. Social anxiety disorder may be caused by the longer-term effects of not fitting in, or being bullied, rejected, or ignored. Shy adolescents or avoidant adults have emphasized unpleasant experiences with peers or childhood bullying or harassment. 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. Socially phobic children appear less likely to receive positive reactions from peers, and anxious or inhibited children may isolate themselves. Cultural influences
Cultural factors that have been related to social anxiety disorder include a societys attitude towards shyness and avoidance, affecting the ability to form relationships or access employment or education, and shame.
Shy children, phobic adults: Nature and treatment of social anxiety disorders (2nd ed.) (pp. 11–46). Washington, DC US: American Psychological Association. doi:10.1037/11533-001
Berent, Jonathan, with Amy Lemley (1993). Beyond Shyness: How to Conquer Social Anxieties. New York: Simon & Schuster. ISBN 0-671-74137-3. Boyle, L.E. (2018) "The (un)habitual geographies of Social Anxiety Disorder", Social Science and Medicine, DsocOI:10.1016/j.socscimed.2018.03.002
Bruch M. A. (1989). "Familial and developmental antecedents of social phobia: Issues and findings". Clinical Psychology Review. 9: 37–47. doi:10.1016/0272-7358(89)90045-7. Burns, D. D. (1999). Feeling Good: the new mood therapy (Rev. ed.). New York: Avon. ISBN 0-380-81033-6. Crozier, W. R., & Alden, L. E. (2001). International Handbook of Social Anxiety: Concepts, Research, and Interventions Relating to the Self and Shyness. New York: John Wiley & Sons, Ltd. ISBN 0-471-49129-2. Hales, R. E., & Yudofsky, S. C. (Eds.). (2003). Social phobia. In Textbook of Clinical Psychiatry (4th ed., pp. 572–580). Washington, D.C.: American Psychiatric Publishing. Marteinsdottir I.; Svensson A.; Svedberg M.; Anderberg U.; von Knorring L. (2007). "The role of life events in social phobia". Nordic Journal of Psychiatry. 61 (3): 207–212. doi:10.1080/08039480701352546. PMID 17523033. S2CID 11620169. External links

Social Anxiety (including self-help links) at Curlie
Support Group Providers for  Social anxiety disorder at Curlie