ANA can be elevated in cases of auto-immune thyroid disease. Would document thyroid antibodies and look carefully at the TSH result as the best indicator of thyroid status. Lymph nodes in the neck can sometimes be enlarged with Hashimotos (auto-immune thyroid disease leading to Hypothyroidism), but this would not account for groin nodes. Your symptoms are suggestive of hypothyroidism, but could also be due to other conditions.
Go to StoptheThyroidMadness.com to read about proper testing and treatment.
Low ferritin levels can also cause fatigue and muscle/joint pains.