Pain causing opiate tolerance?

[ironmics]

I read something awhile back and told it to my friend Jim, about patients in extreme amounts of pain being to handle more morphine before oding, because the pain will keep awake or give you more adrenaline I don't remember. Anyway Jim has a pretty high natural opiate tolerance(except for with codeine, I know really weird), but he's only taken high doseages of opiates more than 20 mg of hydro, more than 10 mg of oxy, and even he believes it was 10mg of morphine IM(doctor prescribed and injected). None of these ever make him feel high enough to understand why so many people want to take these recreationally. Could the amount of pain he was in cause this tolerance. I.E. His back was so bad when he got the morphine he couldn't even sit or stand before he got the injection.