I have a friend who saw a golf sports psychologist. He was an avid golfer and one day his swing just completely went away. He could not hit a golf ball to save his life. He felt fine and had no particular stress in his life but the swing disappeared all the same.
He asked around the course and got a recommendation to a guy who worked with a lot of golfers, even a few PGA guys. They spent some time in an office and also time at the driving range. I don't know exactly what they talked about, obviously there is a personal dimension to that kind of stuff, but whatever was said it worked. His swing came back in a matter of weeks.