Hi

If your scapula is winging then I would focus on strengthening lower trapezius and serratus anterior. You probably have residual scarring in your pec minor so I would focus on stretching that.

Start with isolated strengthening of the two muscles mentioned and then look at doing combined strengthening with your Wikipedia reference-linkrotator cuff. ie: stabilising your scapula muscles while using rotator cuff.

Just be aware that scapula pain can be coming from your neck so you may want to rule this out as a source of your pain.

Rachael