let me take a stab at that and see whether I get it right:
Shoulder impingement is the result of the rotator cuff muscles being unable (too weak, injured) to prevent the head of the humerus from riding up towards the acromion process during movements that raise the arms. The result is that the tissue between the head of the humerus and the acromion process gets squashed, creating impingement.
An inflammation of the bursa is one of the possible results of impingement even though I think that it can stand on its own.
I’ll gladly take you up on the offer of assistance. I see clients where the traditional strategies (even from the PT) seem to fail. I also see clients where the problems bounces back and forth between the two shoulders, leading me to suspect that the neck is more involved than the shoulder.
And by the way: it was an interesting presentation on FAI.