I think there are different types of social anxiety.  I would look at Mercury/Virgo, challenged. Also 12th house/Pisces and maybe Saturn as well for the fear of rejection.

Thank you Elsa. That is helpful.

I don't know how many types of social anxiety there are. What I was thinking about was avoiding social situations for fear of rejection, making a mistake etc. Also being nervous and shaky when socialising.

I would add Saturn in 7th, "fear" of the other as in rejection.

Here is another thread on the topic - Social Anxiety

Wonder about Saturn in 8th.