Question about the cuban press

I've been trying to fix my shoulder for the past several months. Wall extensions give me problems. If I try the full rom my shoulder will slip out, so I've been trying to increase my rom in that shoulder for a while now. Ok, my question is I see in the vid on you tube of the guy doing the cuban press and brings his elbows to a 90 degree angle before performing the ext rotation of the movement. If I bring my elbows up that high it really starts to hurt and gets really hard to do the rotation (I am using very light weight(15lbs)). Same reason I never did upright rows when I was lifting weights. Anyway, is this just a rom problem that will slowly go away if I work on the movement, impingement or what? And if anyone has any advice on how to fix it I'd appreciate it. Btw I do Ido's band exercises, I've read Pain Free and am doing a combination of everything.

Sorry, I guess this should prob be in the joint prehab section.

15 lbs is not very light weight, 4 lbs is.

Guys one thread up there is another question about the cuban press. Keep the forum cleaner, use the same threads

Edit: this would now be a couple of threads down since this one moved up