Could Neuro-Symptoms be related to electrolyte imbalance?

I am a treated hypothyroid patient but over the past few years on thyroid hormone therapy, a symptom that remains unrelieved for me is muscle weakness. At times the weakness is so severe, some normal physcal activities almost leave my muscles with mild injury. I feel this symptom is neurological due to related symptoms including nerve type pains and muscle twitches, headaches that radiate the pain to other parts of my body. Last year, an MRI ruled out evidence of any true neuro diseases however, these symptoms are most definitely significant! There is absolutely no doubt in my mind but that there is a specific cause. I had B-12 levels checked and were good mid-range, about two years ago.
The only blood abnormals I am suspicious of, are my electrolytes. My Chloride level has been slightly elevated above normal, for 3 years (two consecutive tests). My phosphorous/phospate which was included on a more extensive metabolic panel this year, was flagged slightly below normal. I feel possibly having two electrolytes out of balance, are pointing to something. Could it be I need magnesium level checked?
Good advice will be greatly appreciated because the strange neuro headaches, that I feel in my sinuses (absoutely not a sinus condition) and that throbs in my feet and hands, plus the severe muscle weakness (also severe fatigue) must have a cause and I need a Dr. to zero in on it!  

[PaulMD]

Hi there.

Weakness can be indeed directly related to electrolyte levels, and for someone with hypothyroidism, electrolyte levels may indeed go out of hand.  The most commonly implicated electrolytes would include Potassium, Calcium, and Magnesium.  The levels of these electrolytes can indeed go down in someone with hypothyroidism. Also, make sure that your TSH levels are within range, and that the treatment for your hypothyroidism is going well.

Regards.