Shoulder discomfort with long moves

Sometimes when initiating a move with one of my hands over my head and the other below shoulder level I experience a momentary pain deep in the shoulder on the side of my lower hand. This happens infrequently and so far my strategy has been to avoid the moves that hurt. Does anyone have experience with this? Were there any exercises that helped you strengthen your shoulder? I already do external rotations and scaptions regularly.

I have issues with this as well; have no idea what it is though... It manifests itself mostly while campusing while doing max ladders. The shoulder of my low hand pinches pretty badly sometime when I reach through on a long move.

Also interested to hear if anyone has similar experiences and fixes!