I'm sorry you're having to deal with such pain and not getting specific answers. That limbo land is a tough place to be in, as so many of us can attest.
Try to be patient waiting for the test results from the neurologist - it sounds like he is on the ball rather than dumping all symptoms into the fibro basket. I've been there, too. It's not helpful and delays important diagnoses and treatment.
Myositis is an autoimmune connective tissue disease - the cpk, aldolase, etc. are checked to see if you're experiencing muscle damage. I'm interested in his checking the epstein barr serologies. I have been told I have chronic EBV, but nobody seems to know what to do about that. I hope you'll share what you learn about that - and I hope he'll explain if that is specific to anything beyond fatigue.
I had fibro for 10 years before problems started ramping up and finally I was sent to a rheumatologist 3 years ago. I am still "undifferentiated" with connective tissue disease....could be lupus....RA...whatever. Beginning plaquenil as a medication has helped considerably. They still say I have fibro....but that is a separate issue. It isn't uncommon to have fibro AND another AI disorder.
I truly feel for your frustration and feeling defeated. This forum is a great place to learn and compare notes and vent. For me, it especially helped me prepare questions for appointments & not be afraid to ask, and realize I had a lot to learn and it wasn't going to all come from the doctor. Case in point was sun sensitivity - I finally made the connection between my flares and being out in the sun for too long. The doctor had failed to mention that connection.
While you are waiting for more information, try not to stress - as someone said recently you're kind of in the hardest place right now - the uphill climb - but eventually things will level off and you can catch your breath. This isn't your fault, it's not in your head (I really needed to hear that and believe it!). Try to rest when you can, eat as healthfully as you can and just hang in there.
Best of luck and let us know how it goes....