Hey, any updates??? Very curious about what you found out and where you're at right now.
If it helps you I have similar symptoms as you and was diagnosed with hyperparathyroidism.... the PTH & Calcium can flucuate between normal and high... this is completely normal in hyperparathyroidism.
I also was diagnosed with lyme disease & sleep apnea. These two things might also be something to look into... the lyme disease more than the sleep apnea. Lyme disease can cause all your symptoms. All my neurological complaints were relieved by Antibiotics ... I still have muscle weakness which I believe to be from my hyperparathyroidism.