Earlier quoted context omitted.
I found out last year the root cause of my CFS is life-long mercury toxicity (a well understood neurotoxin). I am responding very positively to treatment. I rarely talk about it because people get very upset when I tell them about the evidence of where the mercury came from.
Belatedly, FWIW, I guessed dental fillings. I had mine replaced ages ago. Haven't considered testing my mercury levels. Maybe I should. I had aplastic anemia as a kid, cause unknown, treated with a bone marrow transplant (before they had means to isolate stem cells).
I posted above about a test you can do. Feel free to write me at jbob286 (aat) gmail if you'd like more info. I can point you to a bunch of free resources that can help guide you through the process.