It's very common for people who are addicted to prescription painkillers over the course of many years to get nerve damage in parts of their body, especially so if they are chronically immobile to boot. It stems from them falling asleep or holding themselves in uncomfortable positions that are strenuous on their joints for extended periods of time. When a normal person does this, their body uses their pain receptors to send signals to them that sitting on their leg like this over the last eight hours is uncomfortable and they need to move it, but those same pain receptors its trying to communicate with are blocked. Same with sleeping on your arm in a funny position or something, your unconscious body will move it while you sleep as a response to the pain. This could go for any number of scenarios. I would imagine a combination of poor posture and bad sleeping habits mixed with his extreme pill addiction ruined his body. Obviously just having this issue once or twice isn't going to do anything to you, but over 10+ years or however long Rich has been using for? It can absolutely cause serious nerve damage. Remember, not only was his spine fucked, but he commonly talked about his left arm/hand locking up for minutes at a time, neck issues, etc.
