Like you, I've been dealing with some symptoms that "just don't fit", some of which started developing in my teens (in my 40s now). I have thyroid nodules, but all my blood tests have been well within "normal" range, although FreeTs are below midrange. It wasn't until I saw a holistic MD that my heavy metals were tested. The dr ran an RBC elements test, which tests the metals found in the red blood cells and is a pretty good gauge of what's in tissue. The dr also ran a DMPS mercury challenge test.
They found elevated levels of mercury, in addition to higher than normal (but not toxic) levels of arsenic, cadmium, lead, thallium and manganese. Other than the manganese (which could be the result of my low ferritin level) I'm fairly sure most of this stuff was picked up over 30 years ago.
The mercury's probably from my mouthful of amalgams, in addition to the tons of vaccinations I had as a kid. The rest, well, my parents used to buy old run-down houses and we'd live in them as they were being remodeled. My brother and I were free labor and who knows what we were inhaling (dust mask? what's a dust mask?). Both arsenic and thallium were once used in rat poison. Also, arsenic is currently being used in small amounts by commercial chicken farmers to fatten the chickens for market. It apparently makes the chickens gain weight faster. The lead is probably from old lead paint dust. The cadmium has me a bit stumped, but since I've been around smokers my entire life, that's probably where that's from (there's a lot of cadmium in cigarette smoke).
If you have amalgams, there's no point in starting any kind of chelation therapy. All chelation protocols will leech even more mercury from the amalgams and it's necessary to have them removed before starting. Do some reading about amalgam removal protocols and then try to find a dentist who specializes in this. Just because a dentist is "mercury-free" doesn't necessarily mean they follow the correct protocol to avoid further mercury ingestion.
Good luck and please keep us posted.