Looking to improve your shoulder mobility?
Most people who are start at the totally wrong place. The first place to start is by assessing your rotational range of motion at the shoulder; your internal and external rotation ROM. And if you have a lack of range of motion in either of those ranges, then you likely have shoulder capsule tightness.
If you have shoulder capsule tightness, then working on shoulder flexion (for example) may not be your best starting point. Believe it or not, by addressing the capsular tissue and clearing up your rotational ROM, you can actually improve your shoulder flexion ROM. Yes, without even training for shoulder flexion mobility.
Make your shoulder work like a shoulder. Give it back its rotational capabilities. And it will thank you with improved ROM in all ranges. (Most of the time.) This exercise/stretch can be intense at times. Don’t push into any pinching in the shoulder joint, and don’t cause yourself any pain. No pain no gain doesn’t apply here. Be smart. And if you actually have shoulder pain, get it assessed before attempting this stretch to see if it’s right for you.