dont know. twitches could be from facial nerve damage, but probably not. twitches from facial nerve damage are 24/7. not '50%' of the time. more likely myokymia...benign lid twitching from lack of sleep, stress, too much caffeine, or other systemic problems. can be helped with warm compresses, topical antihistamines like the newly-over-the-counter drug ZADITOR, and obviously treating the underlying cause in the case of systemic disease. possibly related to your bone tumor.
dont know about the headache. probably is neurological even if the neurologist cant diagnose it.
dimmer vision in one eye implies some sort of nerve damage to that eye. thats definitely neurological. one of the big causes of 'dimmer' vision in one eye is MS. i am certainly not diagnosing you with MS or even suggesting that you have it. just pointing out this this, too is probably neurological.
Low magnesium within the cells can cause muscle twitches and other symptoms.
If you decide to take a supplement, you need to pay attention to the form of the mag, as the intestines have difficulty absorbing many forms.
Magnesium glycinate is one form that is more easily absorbed...you need to look at the list of ingredients.
For example:
http://www.iherb.com/store/ProductDetails.aspx?c=Herbs&pid=SNS-00803
Almonds are high in magnesium. You can buy a pound of almonds at the grocery store, and eat several ounces per day.
You might need to take magnesium for quite a while, or the symptoms may come back.
Wishing you the best,
Carol