My job for many years had me walking a lot. Up and down stairs often dozens of times a day a double set of stairs so two story equivalent. Plus crawling around

My job for many years had me walking a lot. Up and down stairs often dozens of times a day a double set of stairs so two story equivalent. Plus crawling around running cable on floors or in ceilings. Lifting equipment from 50 to 300 pounds (with assistance). Now I'm at a desk and two years on I often catch myself shaped like an S. Engrossed in a problem my posture has become bad. Plus I haven't done any exercise in two years so my muscle tone and cardiovascular has has never been worse. Last week whatever I did or whatever series of events led up to it my right shoulder just exploded in pain. My clavicle at my neck was popping, my muscles felt like they were being pulled downward by an invisible meat hook stuck in my shoulder. I took a day off, took some anti-inflammatory pain killers. But it took a good week to get over it. I blame my poor posture and being desk-bound but my poor health also had a part in it.