That’s an ever-changing category, though, as medical technology improves. Bone fractures would have been more difficult to observe directly before the invention of x-ray machines, but that doesn’t change the underlying physical condition.

GPs aren't always sufficiently specialised to do a detailed diagnosis, but in my experience, a good physical therapist should be able to find the problem. (They have in my case, whereas the GP just asked some vague questions and decided it's probably some form of RSI.)