If you live in England you can self refer to your local IAPT service. They'll triage you and then assign you to either high or low intensity talking therapy. Current wait times are good.

Be aware that social phobia and social anxiety isn't just being anxious in social situations! here's a good guide to treatment for people who have social anxiety at the more severe end: https://www.div12.org/wp-content/uploads/2014/09/Comprehensi...