How I solved my shoulder immobility

For the past three years Ive been doing the Starting Strength LP off and on and I felt like I could never get the bar in the proper position for a low bar squat. To make matters worse I was just doing overhead presses as the program prescribes. I believe this lead to unbalanced delts because the press seems to target primarily the front delts and the triceps.

Im getting older and I dont feel the need to be as strong as possible. My goals have shifted to aesthetics more so. So I started this modified split.

Day one

Shoulders
Back Squat

Day 2

Back
Chest

Day 3

Arms
Deadlifts (light weight)
Front Squat

Im a month into this shoulder routine which is high rep body building. I got the routine from a Joe Grage Youtube video. It starts with the rear delts, cable fly superset with incline "prone" dumbell flys, then lateral delts with a cable lateral fly super set with lateral dumbell flys, then a dumbell press super set with upright rows with plates.

Ive started the workout with shoulders after reading a poster here talking about how squats at the start of a workout will tax the rest of the work out. When I started warming up for squats I saw that I could put the bar much further down my back on the scapular ridge. I feel like I was able to do a real back squat today for the first time due to this shoulder body building routine. It felt awesome and the squats felt easier as I was engaging the posterior change with better bar position.

I also was getting a lot of shoulder pain on both overhead and bench presses but now the pain is gone. I think that I have been strengthening my medial traps and that may also be the reason for the improved mobility. I hope this helps any of you guys having trouble with shoulder mobility.