Ask a referral to a speech therapist / occupational therapist. This is a person who I see after the surgeries I've had on my tongue, to help me regain better speech and to ease up the scar tissue from the surgeries ... she helps with both my tongue and my neck (because I had surgery there too, and radiation damage). If there is still scar tissue from 20 years ago, that in itself could be causing you problems. There are, believe it or not, massage and stretch techniques that a good therapist could show you to work on that. Not only would this help your stress and give you something to do, but the right therapist might even feel something the doctors have missed, if they've gotten frustrated to the point of impatience. I've been really blessed with the therapist I see ... she's amazing and has given me help on so many things that I wouldn't have expected. And it's a route you haven't tried yet, and with the scar issues, it's something that would likely even be covered partly by insurance. Worth a shot.

Good luck! It's probably not what you are afraid of, but you still shouldn't have to keep suffering whatever it is.