Regenerating creatures ( Trolls, Ogre Mage ecc. ) pain trheshold

[Conradine]

Creatures who are able to regenerate wounds , like trolls or ogre magi, perceive pain ( from sources different from acid and fire ) in a different way?
If a troll is stabbed through the stomach, he feels the same excruciating suffering an human would feel?

[Selion]

I broke both my arms in two different occasions. The real pain kicks in after a few minutes, at the beginning adrenaline snuff it all and you mainly have fear of losing functions of your body parts.
If i'd knew they would have been just fine in a few seconds i think the pain would have been totally bearable.

[ExLibrisMortis]

I'm sure regenerating creatures feel that they're being stabbed, but I would think it'd be less painful, and they wouldn't have the same reflexive responses to pain, because those are ultimatly derived from the need to protect the body from serious harm, and most things aren't serious harm to a troll. By RAW, though, no amount of regeneration protects against pain (i.e. sickened/nauseated, nonlethal damage, torture-assisted Intimidate checks).

[Zaq]

All non-favored damage is nonlethal, and nonlethal damage can certainly be hella painful, but I think it’s reasonable to ad-hoc that it’s going to be less painful than lethal damage. Hard to draw parallels to human experience because it’s difficult to find anything in reality that clearly qualifies as “nonlethal damage.” You don’t have to be a trained martial artist to kill or permanently injure someone with a lucky/unlucky punch (is it common? No. Does it happen? Indisputably), and it’s not good for human bodies to take any kind of trauma that the game would call “nonlethal.”

I feel like a minimum of one Monster Manual specifically describes trolls as not caring about pain, but I don’t recall offhand which MM or which edition had that fluff text. Doesn’t necessarily mean that the same guideline can be generalized to non-trolls, either, though there’s plenty of wiggle room for GM interpretation.

If we want to really bring in concepts that have absolutely no place in the silly game world, you could make an (absolutely not in any way RAW) argument that trolls wouldn’t feel much pain because pain is a warning signal of danger, and a troll’s body isn’t in danger from non-favored damage. Discomfort, sure. They have nerves. But the troll’s body isn’t threatened by a blade the way it is by a flame. (Yeah, this line of reasoning has an awful lot of flaws in it. Like, an awful lot. Bodies are, in the aggregate, really bad at self-assessing true danger. And assuming any sort of evolutionary biology in D&D’s wacky magic-soaked fantasy ecosystem is straight up not wise, not to mention that biological functions don’t always stem from or contribute to what we might expect. But the discussion is already well outside the scope of RAW anyway.)

[Kyutaru]

Pain is a response you control. Whether athletes, soldiers, or ancient warriors, you can learn to control your pain response. This allows people to do things that go far beyond what a normal person's pain threshold would be. Some people even remap pain to pleasure and take ecstasy in torture. Regenerating creatures have likely suffered more pain than a man could feel in a hundred lifetimes owing to their capabilities keeping them alive even in the face of lethal damage. That which does not kill you makes you stronger is a saying related to enduring pain.

The troll no longer feels that excruciating pain. He's felt it so many times that it no longer shocks his nervous system. A baby falling the first time will cry a river of tears at how terrible the experience was but an adult can fall off his motorcycle going high speeds and show little more than a wince.