...Her doctor has told her to stop playing the cello...
Maybe temporarily to let it heal. (doctors never know anything, ha, lol

, especially since he/she probably doesn’t even know how to even play the cello)
What does she do to get tendonitis? My high school type writer teacher always got tendonitis for typing weirdly and said that we could get tendonitis for typing weirdly also, like bending my hands back while typing (and hurting my wrist) instead of the palm of my hand being level to my forearm like it should be. I got tendonitis once; it could have been from practicing too much or just holding something weirdly, like the bow or cello itself.
HMM? Tendonitis just doesn`t come from nothing. It has to come from putting stress on the wrists some how?