I’ve never broken a bone (yet, knock on wood) but I have had arthritis for a number of years and I get migraines, and that has definitely skewed my pain response. If I’m limping because of hip pain, it probably means I feel like I am being stabbed with each step and possibly also vaguely nauseated due to pain. Most of my friends are quite surprised when they learn how bad some of my joints look on X-ray, because apparently you can’t tell. But my mom and dad are both the same mostly - don’t complain about pain much. (Unless my dad has a headache, which is usually the end of the world even though he gets normal headaches, not migraines or clusters. So I think there is an element of tolerance related to type of pain also - pinched nerve pain doesn’t rank as high for me on an absolute scale as some other pain, but I don’t tolerate it as well - it distracts me more and makes me feel sick, etc.)
Meanwhile one if my housemates now shrieks in pain over relatively minor things and seems to not even really be aware she’s done it. Like her body responds to the pain without checking in with her brain first. I do kind of worry that if she has a bad accident some time we won’t respond fast enough because we won’t know the difference between that and normal bumps and bruises. So I wonder if there is some kind of reflex thing for some people? My late MIL could completely not control her startle response - she yelped every single time even if she was trying to be quiet. Brains are weird?
I will say, I have had some pretty painful hips. Obviously with me the arthritis factors in, but one area that gets sore isn’t actually in the joint, but rather where the muscles and tendons and whatever attach at the top of the femur. I can kind if see how if you landed badly there it might be surprisingly painful. (Kind of like when you get your “funny bone”?)
I do think a pain scale is a good idea. You can maybe try journaling as well, to help her get an idea of how different things rank for her. Bonus is if she does seem to continue to have pain tolerance problems, you will then have that data to take to a doctor. There is a pain scale online somewhere that ranges from ignorable to you can try to ignore it but it interrupts to OMG WORST PAIN EVER MY BRAIN IS GOING TO BLEED OUT MY EARS TO ESCAPE THE PAIN essentially. That might also be useful to use as a reference for her in thinking about not just how pain compares to other experiences, but how much it is actually bothering her or causing problems.
I have noticed that sometimes the more you fuss over little pains, the worse they seem to be, even within yourself. It’s like you keep reminding yourself that you should be in pain! Because paper cut! So even though it is minor it can be more distracting than a more major injury. (Well, and some paper cuts really do hurt a lot. But you know what I mean? It is like mentally poking the bruise.)