Mike–
When did you first notice the issue?
Had you done something different from what you did in the past?
Where is the pain in your shoulder?

You need to identify what is causing the pain in your shoulder so it can be fixed. Without identifying the cause the pain will continue.

Using a stem machine is going after a symptom of the pain not going after the cause of the pain.
It could be several different things.
Episode 16: Overhead Squat Prep Part 1
Episode 17: Shoulders and The Back Squat “Rack”. And Darth
Episode 18: Free Your Scap, Free Your Mind
The 500th Video; Great Sub-Scap Shoulder Smash Drill