The Ready State Virtual Mobility Coach is like having a virtual Kelly Starrett in your pocket.
Not sleeping on that side is a great start.
Episode 190: Super Chris Spealer + Internal Shoulder Rotation
Lacrosse ball to the pec and around the clavicle will address the front of the shoulder.
Looking to reduce inflammation is most likely why they said no upper body work.
Working up/downstream of the issue you’ll feed more slack to the area.
The episodes in the post above address internal rotation.