My experience with pain meds: I still felt pain, but I didn't care anymore.
The problem is imo that previously, when these studies were done on opiates and their effectiveness, the dosages were significantly higher. Since they are trying to give as little pain meds as possible these days, for all kinds of reasons, they aren't much more effective at dulling pain than an Acetaminophen or placebo. Speaking of which, if you're allowed to take an actaminophen with what they gave you, it will make it much more effective. Also, grapefruit juice is a potentiator.
Good luck.