Due to major shoulder issues Ive avoided surgery on for years, I now do squats with my hands all the way outside the collars. I grip the ends of the plates. I couldnt figure out why my shoulders hurt so bad on squats (I used to be narrow grip low bar), but a sports med guy told me about the pressure of the internal rotation blah blah Im not exactly sure the techno stuff about it...I changed to gripping the plates outside the bar and have been fine since.
I dislocated my shoulder in college football, they said I needed surgery but I didnt want to miss spring ball so said no...then in grad school in jujitsu I dislocated it the other side, so they said both the front and rear of my capsule was "bankhart lesions" or something, basically I think they said I had a spot in front and rear where it was punched out. I have detached tendons, a hooked clavicle which impinges my rotator cuff, and spurts in my AC joint. I still squat fairly heavy (sets with 405), clean moderately heavy (sets in the 255-305 range for 3-5 reps), snatch, and overhead press. I dont have any major pain unless I do too much benching or other upper body work. I stick to close grip. Again I dont know all the technical stuff, but the doctor joked I needed major surgery and someday will have to get it. For now I survive I think by keeping all the back and shoulder muscles in check.
Moral to the long boring story, if you cant find a way to rid the pain, widen the grip. Good luck!