I would do a couple of things. Unless you have surgically repaired shoulders with minimal range of motion, you inability to hold the bar for squats would concern me. I would work on shoulder flexibility. Where you trying high bar or low bar squats? Bar position can affect shoulder flex too.
I love front squats. There are also zercher squats and BB hack squats. All of these are good alternatives but with limitations. Fronts and zercher can not carry the weight of back squats but activate the muscles in much the same way. Hacks hit the legs a bit differently, but you can use as much weight as you can hold at arms length behind you.
David, Husband, Father, Pastor
(Yasen Miroslav Zavadil)
2014 100%RAW American Challenge, May 31, 2014:
Deadlift 375 PR
Total - 843 at 50 yrs 199.6 lbs
Shooting for a 900+ total for next meet. (see quote below)
"If there is nothing you can improve on, your standards are too low!" - BAMA Strength Coach Scott Cochran
1Co 9:27 But I discipline my body and keep it under control, lest after preaching to others I myself should be disqualified