Try the speech therapist route, then. If you get one as great as I had, she (or he) should know a LOT of exercises for scar tissue in the tongue. Who knew that could be a specialty? Or that tongue massage was a thing? LOL. But it really did help recover a lot of maneuverability for me, and worked out a lot of the scarring ... if that happens to be what's causing your pain, then that's where you'd end up for treatment anyway. Might as well see if they'll give you a referral ... our doctors can be great specialists, but they don't spend solid minutes massaging our tongues the way a therapist might. (Yes, totally weird, and it's to teach us how to do it ourselves ... but they sure learn a lot about the way things 'should' feel in there and give tips how to make it work better.)

Anyway, good luck and please keep us all posted! Whatever you find out is bound to help others, too. ((hugs))