A lot of people have trouble making friends. I don't know much about your social anxiety and my experience with such is limited to my stutter, but how much do you speak with people on a daily/weekly basis, outside of work. Maybe start small like asking an attendant at a store where something is, or practice making phone calls inquiring information about something. But without knowing more about you or where you are with your stutter it's hard to give suggestions. There are a lot of meet up options for sports or running or general hobbies. Going to one to those, meeting people there is always an option.