Health question.. rotator cuff?

I have a torn rotator, about a inch right at the bone, after 3 years of the runaround from 3 Docs the most recent one asked if I had an MRI yet? NO not yet, well that’s when it was found, the others said it was just a sprain. I slid off a chair scooters extended my arm to catch myself. But the funny part, it had been a dull ache for 30 months till one day I was replacing a capacitor on an electric motor and it shocked me, 450 ac volts. My elbow and shoulder quit hurting since then, maybe once in awhile now. Doc said 15 minute operation, 3 weeks in a sling, therapy for 6 months and MAYBE I’ll be back in a year. That’s been 3-1/2 months since and still not sure if I’ll do it. Might try those exercises. I’m 73 and not sure if it’s worth it since it don’t hurt after ‘shock’ therapy