>what causes the pain?
Good question.
some is caused simply by bodies growing old. people may live longer but parts wear out. It's become more and more difficult to obtain pain relief, even tho only a small % of those receiving opioid pain relievers abuse them. have suspected for a long time that the withdrawal of pain relief is to shorten the lives of those with chronic pain. Ask anyone who used to have a script for darvon - a mild pain reliever.