I mean, that’s part of pain tolerance. It isn’t just how much pain you feel, it’s how much you can take.
Chronic pain has taught me a lot about what is and isn’t bearable. Things that when they were new would leave me sobbing, I now don’t even show more than a frown and gritted teeth for on a good day.
Part of that is taking the pain, putting it in a little box cake “I will not fucking quit” and throwing that box into the depths of the mind where it can’t bother you for a while. Your body still hurts, you still know it hurts, but you keep going until you can’t, and the pain can just fuck right off.
Now, let me stub my fucking toe while doing all that and it cuts right through all of that and says “nah, dawg, you gonna feel this”. Different pain, and acute.
So, little shit like shocks and needles in muscles, and the like, you know they’re coming, and they go right in the box with the chronic, and into the oubliette of agony.
That kind of pain testing? That’s totally within mental techniques’ ability to ignore. Your pulse will still change, blood pressure too, but it’s still a distant thing that won’t reach you for a while.
But everyone is different. You can take two people with the same injury, and they’ll tolerate it differently, even if they’re siblings of the same gender.
Part of that is indeed built in, but there is always a psychological component to pain perception.
Now, please note that I’m not saying that walling pain off and ignoring it until you’ve injured yourself is a good thing, much less better than letting pain guide your actions so that it isn’t worse later. I’m just saying that the green text is realistic, and the person responding like that may not be bullshitting, they may just have worked on managing pain.