Why aren't medical Dr's held accountable for drug addiction..if they have been supplying them for years

if you are put on narcotics for pain and three mos later they do m r i and can not find anything so every month you go back to get your perription and after awhile they up the dose... 2 years later a new dr a back specialist sees on reg x-ray and naked eye a fractured tailbone... sends you to pain dr i was on 380 10mg percocet...380 10mg methadone for over 2 years i was on narcotics...now addicted i am in pain daily and when i mentioned this to drs..they sent me to methadone clinic...