CT scans, particularly of the liver and brain and GI tract are important. Chronic-Fatigue-Syndrome is pretty vague stuff, I am still clueless myself. Check the pituitary gland with the scans.
Make sure if someone here did not post it yet, to go to stopthethyroidmaddness.com and read about the REAL tests you should be getting to screen thyroid. Rigorous, ruthlessly persistently thorough thyroid testing is the only way to rule it out, and thyroid effects everything and is so confusing.
Heavy metal testing, aluminum, organophosphates, agricultural wastes, etc, mercury. I have not done these yet. Curezone folks seem adamant on parasites. MY two cents, is agriculture sourced environmental toxicity.
Get testosterone, androgen, estradiol, SHBG, tested. I tested mine and my T is off the map, and so is my SHBG, so I may not have any free T. That is like low T. Low T will wreak havoc.