I have experienced rotator cuff pain, various back pains, and sciatic pain. Fortunately not all at the same time. Each of these can be debilitating, that is they can prevent you from functioning in your normal life.
When I had rotator cuff pain my doctor wanted to operate! I met an acupuncturist and went in that direction instead. After a few treatments the pain was gone and I started researching exercises that might help. As a result I now have a few routines that I have incorporated into my regular workouts as a preventative measure. I have had not rotator cuff pain in 25 years!