Hi. I rarely post, just read usually. I wondered what type of shoulder instability you are refering to? I have dislocated my right shoulder several times in the past. I know for me working the shoulder muscles with weights VERY carefully over the last several years has, I believe, helped to stabilize my shoulder as I haven't had any recent dislocations. I don't know if this is your problem, but maybe some food for thought. Good luck with the Dr. appt.