I was told by my orthopedic that my shoulder spurs were caused by continuous repetition of a defined work, sport, etc. They are growths on the end of bones at their joints. When the joints are used it causes pain and irritation. A lot of people have them, but experience no pain or irritation. It’s a form of arthritis. Mine were caused by constantly chopping,splitting, stacking firewood and weightlifting. I have been a wood burner since I was 10. I am now 60 and have felt the pain from spurs. Believe me, it is not pleasant. I bought a log splitter last year to avoid surgery. I hate being dependent on it to do the work I love doing, but I am not in pain anymore and have been able to put off surgery for now.