Chronic fatigue and fibromyalgia are often symptoms of hypothyroidism. Most doctors will just check the TSH and if you're in range declare you fine. Most doctors AND labs do not follow the American Association of Clinical Endocrinologists (AACE) recommendations of TSH range being 0.3 to 3.0. Back in '95 I was diagnosed with fibromyalgia because my TSH was 5. With the new recommendations, in 2004 I was diagnosed with hypothyroidism. I suffered with undiagnosed hypothyroidism for almost 10 years.
Since I've been on natural thyroid hormone treatment and began addressing my adrenal fatigue, the aches and pains are slowly going away. I had low b12, ferritin and D levels that I had to get up, all of which contribute to fatigue.