My son's is diagnosed with Fibromyalgia like me, but has other autoimmune problems. He gets very, very ill if he has a virus, has icepick headache, very bad vertigo and goes faint a lot, is tired all the time, has NASH liver, endocrine problems and skin rejection at his extremities.
Recently, I found out that I may, or may not have post Lyme disease syndrome, instead of, or as well as Fibromyalgia, and seen as he has never been bitten by a tick but I have, a Fibromyalgia hereditary tendency seems slightly less likely. I suppose there could still be a tendency, though his was triggered by glandular fever?
Diagnosis of Fibromyalgia seems to be a matter of saying - "we don't really know what is wrong, though we do know there is something genuinely very wrong, with certain brain function differences back this up" So it is called Fibromyalgia, and we must go away and see if something else happens to contradict, or shed light upon this diagnosis.
I understand that doctors and researchers can't know everything, and often have to just treat the symptoms, but knowing that doesn’t help us to feel reassured that some other important aspect of our health isn't going seriously wrong in the meantime. It is depressing enough when it happens to you, but when it happens to your children too - and there is still no better explanation!