You might find this talk a good place to start. https://www.lister-sinkinstitute.org/tedx/ Barbara Lister-Sink was at the top of the concert piano world in the 70s until she was injured due to bad use. She then began seriously studying the development of keyboard technique and how it is that certain pianists (Horowitz, for example) could play perfectly into 80s, and others were out of commission by 30. She has tried to combine insights from objective and technological studies of the body with Alexander technique with the way keyboard technique was taught in the 20th and preceding centuries, and her work is even more important for organists, who use (and therefore tend to injure) more of their bodies. Several of her students now offer instructions to organists, and I for one can say my career was saved in this way.

I was lucky that our dean in the music school was a student and proponent of the Alexander technique. I used to have to lay on the floor to relieve the pain after practicing piano. Learning better posture was a game changer. Google will be your friend here. I teach even my young piano students the basic "marionette" trick where you pull a string up from your head to bring the spine into place. Good luck. It is no fun to be in pain while you play. Personally, I struggle with knee pain using the pedals, so I may have to brush up to see if they have anything to say about that as well.