You have to earn healthy shoulders. If you're diligent with your daily maintenance work, especially before training, staving off achy shoulders is easier than you think.
Need some inspiration to keep things fun and challenging? Try the star pattern pull-apart. This banded pull-apart variation uses three different hand variations to hit the scapular stabilizers at multiple angles.
Star Pattern Band-Pull Apart
The key here is slow and controlled execution. Start out with 2-3 sets of 5 reps in each direction (15 reps total) per set. Your pain-free, bulletproof shoulders will thank you.
The world famous spine expert puts the whole spinal flexion, rounding-the-back issue to rest, along with describing the proper way to train core rotation and much more.