Form looks pretty good really except for hand position. It is pretty wide and right hand definitely isn't on the bar quite as much, which is a little interesting since you mentioned the problem was your left shoulder.
I would work on really opening up those shoulders, a few band dislocations before squatting isn't going to get it. You are going to have to really spend some time working on soft tissue quality and mobility. I would recommend really going at the pecs and anterior shoulder with a lacross ball as well as some mobility work.
Here is a good start https://www.youtube.com/watch?v=V-nk-wqPFxc. This guy has a ton of videos and all good stuff.