They go hand in hand for sure. Speaking personally, of course, it's only until last year that I saw any connection between stuttering and social anxieties. Some of the ways in which I've tackled my speech in the past can also be applied for social anxieties. In terms of finding ways to be relaxed; disconnecting ourselves from our thoughts; tackling our problems head on. I go into more detail about it in this video here: https://www.youtube.com/watch?v=-PW1HuNmpGk