Mild and fluctuating Creatine Kinase levels

[adam13579]

I am a 23 year old male. I had my Creatine Kinase levels checked about 4 months ago which was around 600 U/L. My GP checked it again 3 months ago and the results came back yesterday at 292 U/L. At last week's check up my CK was 406 U/L. They checked my Vitamin D levels which was at 23. The doctors also ordered an ESR, ANA, CBC, CMP, and C reactive protein, all normal. She then referred to a Rheumatologist/Neurologist. I will be getting some more autoimmune tests and the aldolase test. I am concerned because I am having muscle aches, twitches, and fatigue. I do exercise but not too hard.

Is it normal for CK levels to fluctuate if you have any of the MD diseases?

Could my Vitamin D play a role in this?

[adam13579]

Does anyone have any idea what this could be