If you have pain and you know why, you'll generally volunteer that information to your doctor. If you have pain and you don't know why, they will look at the area that hurts. If there's nothing obvious there, they'll give you painkillers, because all the safe money is on the idea that no matter what they try, they'll never be able to eliminate or even identify the cause of the pain. This is what you want them to do.
Looking at it from the doctor's viewpoint: Does this patient complain a lot? Is this complaint important? Hard to answer, expensive to find out with current technology and discoverability of relevant knowledge, techniques and advances is an everyday battle that hasn't been addressed consistently.
Some patients, like my grandmother, avoided complaining to not seem "fussing" when she dismissed heart disease as indigestion, ultimately had to have a quintuple bypass and coded three times in the OR. Slowly, she came back but it gave her back more energy than the previous decade and she's still alive.
well, we're not, and unless you are billionaire/us president, we won't get there in our lifetimes, nor our children's. fiancee is an internal doctor in one of biggest hospitals in Switzerland (read - you don't get much better public healthcare anywhere in the world), and they are
a) overwhelmed by amount of people, especially old whose bodies are just a massive clusterfuck of issues - welcome to being old. all they try is to keep them somehow alive when today this was failing, tomorrow that etc. there are simply no resources in medicare to treat your non-fatal condition which doesn't stem from something obvious.
b) 50% of people are sometimes in pain. each body is unique. what makes one thrive brings other to its knees.
c) as said here before, doctor's role is not detective investigation, that's research. doctors these days are overwhelmed with patients and must prioritize their incoming queue, even if it's with somebody's pain. Every patient also means hours of bureaucratic hell, same for incoming as for outgoing ones. that's why rich people have private health care - it's not about having best doctor available (same as you don't find brightest IT people in say SAP consulting), it's mainly about having someone dedicating as much time as needed to you.
I wish it would be so too, but that's simply not reality now
In middle ages, millions dies of plague 'with no apparent cause'. I guess humankind just said 'ah, these things happen, let's not investigate further'. </irony>