Thanks for your question. I'm happy to help you today.
Online counseling is a growing field, although there's some professional debate over whether it's truly a helpful substitute or replacement for in-person treatment. If you have an interest in psychology, obtaining an online degree from an accredited university (if your social phobia prevents you from attending a university in person) or taking some introductory classes in psychology or mental health counseling would be a good place to start, just to get your feet wet. Reading some intro books can also help you decide if this is a path you truly want to pursue as a career option, or if you just have an interest in learning more about yourself, as a sort of "hobby".
A lot of therapists offer online counseling because it can be used around the world, and patients who live in areas without easy access to mental health services (but have internet access) can obtain professional help as well. The thing to be aware of is that there's no real regulating body for online counseling, so a lot of people call themselves counselors without any true mental health training (so again, if this is something you're truly interested in, getting some professional training under your belt is a must).
Just do a google search of "online counseling" and you'll get an idea of what I'm talking about - and you can see some examples of reputable therapists who've set up successful online counseling practices.
You don't have to let your social phobia prevent you from pursuing your dreams. It's certainly worth a shot, and I think online counseling can be a good way for you to help others without having to deal with the increased anxiety
you might have from helping them in person.
I wish you the best of luck with your decision. Please let me know if you need additional assistance.