Yeah high school can be rough sometimes :? Theres so much peer pressure about how you look and who you hang about with,and if your not perfecty "normal"lol or maybe average is a better work... eg too skinny,overweight,tall,small or stand out in any way its picked up on.It doesnt suprise me that most people with sa/sp find they started having problems at school.
And i really understand about being scared to ask for help.. i was the same,and tbh i didnt really understand what was happening to me at the time.I was scared people wouldnt believe me and all sorts of daft things.Alot of people find it so hard to open up to people about our illness,(theres been so many posts on here like "how do i tell my doctor ect").
Anyway by advice would be if you decide you want to try and get help go and see your doctor,write a list about how you feel beforehand and take it in with you incase you get a bit anxious and tounge tied.Or say you stummbled across a site about social anxiety and found it really described the problems your going through.