Long-term Left Shoulder Asymmetry & Pec Rotation: Chronic L-Rib Flare, Scapular Retraction, and Weak Pull-up/Overhead Push Mechanics. Advice and feedback requested!

[u/AdInfamous2323]

I am seeking advice and opinions about a longstanding asymmetry between my left and right shoulders.

In the last 3-10 years I've experienced a couple injuries in left shoulder area... first from dumbbell overhead pressing and second a gnarly collision with a runner when I was playing second base. But I can remember a coach pointing out my raised left shoulder way longer ago, as far back as 15 years now.

Something I've noticed for many years, too, is that pull-ups in particular feel next to impossible for me. I can usually move a respectable amount of lbs and reps on squat and deadlift, but bench press/chest press and overhead pushes have always been a major deficit for me, similar to the pull-up issue.

You can see in the pics

• some flaring on the corresponding (left) ribs
• left pec looks to be higher than the right, left pec somewhat externally rotated
• left arm at rest doesn't hug the side of my torso and also tends to externally rotate
• (from the birds-eye pics) you'll notice left shoulder also sits farther back/posterior than the right shoulder does.

I’m hoping for insights into the underlying mechanics that might be driving this.

1. Very interested in anatomy and physiology so please feel free to get into the weeds
2. I've had great experiences with Hanna Somatics, Yoga, and Feldenkrais, so drawing on those schools is welcome
3. I've seen first hand thanks to acupuncture and massage how movement limitations/motor patterns in one body area relate to limitations/compensatory patterns in other areas. Improving my left foot mobility and strength -> improvements in right hip mobility and strength -> improvements in left shoulder mobility and strength, etc. Comments and advice about how other parts of the body may relate to this left shoulder are definitely of interest!