Shoulder Imbalance

Just wanted a few opinions on this strength imbalance/injury that could account for my shoulder weakness. My shoulders have always been a weak point in my lifting, with my overhead press far behind my flat bench. I’ve also notived that my external rotator strength is fairly developed. For instance, today I did some seated external rotations with a 4 second negative with the 15 pound dumbells for 10 reps on each arm. I also did some lean away side laterals today with a 1-2-1 tempo(holding 2 seconds at the top) and could only muster to do the 10lb DB for 2 sets of 10 each arm. I can close-grip bench press 260 if that helps. I train westside. Bench has always been my weakest lift, and anytime I perform overhead movements for more than a few weeks my overhead as well as benching strength goes down the drain. Oh, I can front plate raise the 35lb plate westside style an easy ten times. So my posterior and front delts seem to be fine, but my overhead pressing and side lateral strength suck!