It sounds more of a neurological and possibly adrenal issue than one related to rheumatology, however it could involve any or all of these.
Things to rule out:
1. PTSD or chronic mental and/or biological (hidden) stress.
Adrenal stress profile - FYI as a ref. visit BioHealth Labs site.
2. Spinal cord compression abnormalities
3. Nutritional deficiencies such as: Methylocobalamin B12 (neurological and bioavailable form of B12-need to have MMA test for this), tissue levels of magnesium (not serum), vitamin D, cholesterol
(low cholesterol affects hormone synthesis and neurological function)
4. Neurotransmitter dysregulation/imbalance.
5. Low thyroid function. (FreeT3, Free T4 and Reverse T3 tests)
If you need any details regarding the above let me know.