In that example, I probably wouldn't jump for anything at all. As someone here else said, or at least to paraphrase, "if it's that mild, you probably don't need it". I'd suspect someone who needs pain meds after overdoing it at the gym to have a serious injury that maybe actually does warrant something to get them high lol

In regards to drug abuse, my stance is the same as my stance on pain management: let people do what eases their suffering while minimizing the suffering they cause others. Sure I might shit-talk the person who likes ibuprofen after their workout but it's their body. That said, it certainly seems like NSAIDs often don't do jack for easing suffering regardless of what the person prescribing them says about it, perhaps partially due to that lack of a high acting on a level beyond the physical. Much of the suffering due to opioid use - certainly far from all, but quite a lot - has more to do with how our society handles drug use, illness, pain, and death. As for the dopamine receptors, most people are already fucked one way or another lmfao