How do so many people become addicted to pain meds?

Access & Need: Easy access (drugs, sleep meds, alcohol) and ever increasing need to avoid different sorts of pain: physical, emotional, personal relationship, low self-esteem. As the body receives more of these external chemicals, it makes less of its own natural endorphin-like chemicals forcing it to "get" them from the outside world. There is individual susceptibility, but usage can increase in some societies!