Pain is the mental reaction, not the whole process (of course, mental reactions are themselves physical processes, but that's a different discussion). When you take an opioid, the pain goes away, but the physical process that was previously causing it doesn't.

This is such a one sided dogmatic view of how the body works and heals that I honestly don't know where to start. I've seen enough evidence of bodies healing themselves just from changed minds. The truth is the synthesis of western scientific reasoning and eastern mysticism and holistic thinking. The problem was always blind faith, dogmatism, which is exactly what you're doing.