*disclaimer: I'm not a doctor.
*second disclaimer: I'm only attempting to provide a perspective. NOT a diagnosis
But I am currently in PT for shoulder impingement syndrome, which I happened to get from playing too much competitive (club-level) tennis each week. It's in my non-dominant, left shoulder, and is probably the result of frequently swinging hard, and brushing up on a two-handed backhand, with non-ideal technique. My condition particularly affects overhead arm movements. I'm told that I can continue to play through it as long as symptoms don't worsen.
What I have learned:
1. The shoulder, like the entire human body, is ultra-complex
2. Muscles, tendons and joints can become inflamed through repetitive-use (after all, you wouldn't redline your car engine for 30 minutes at a time!)
3. The body (tissue) WILL heal through rest, cooling (ice), heat(!), stimulation, circulation, massage, strengthening, stretching and other treatments. I've improved a lot after 2 weeks (1PT session per week)
4. It is possible to play through many minor cases of inflammation.
5. Patty Mills is a star from down under and I'm so happy that he is a Spur