High CPK on blood test recently done (8/25/09)

I recently had blood work done and my cpk was 429. Should I worry? What could cause this. The normal range is 38-234. I have RLS, Cramping in my feet that occurs nightly and then some which causes my balance to be poor. I have osteoarthritis, a bulging disk at about L4,L5 and the discs are poorly alligned. I have had a 4 cm tumor removed from the Left base of my skull which was nonmalignent and have recently requested a follow up Mri to be sure it has not grown back. My doctor says a cat scan will do. My doctor is also not suggesting that this elevated CPK be checked out. Is this something I should worry about since no one else is? The only other values that were slightly high were Blood urea nitrogen (21)Phosphorus (4.9) MCH (32.1) AND THE DIFFERENTIAL FOR SEGMENTED NEUTROPHIL WAS 72 (NORM 25-62 AND THE lymphocyte was low (18 (norm 20-48). Can you tell me what these mean especially the CPK since my Dr does not seem to think it necessary to even discuss this further with me?