Re: Can candida affect nervous system ?

Generally contracted muscles like that and twitching indicate a lack of magnesium and/or high serum calcium.  Calcium contracts muscles while magnesium relaxes muscles by displacing calcium.

Low magnesium can be from poor absorption or loss of magnesium such as from high carbohydrate or alcohol consumption.  Elevated serum calcium most often results from hyperparathyroidism or pseudohyperparathyroidism.  Hyperparathyroidism can be triggered by low vitamin D levels leading to parathyroid nodules that increase parathyroid hormone (PTH) release.  Pseudohyperparathyroidism can occur from the excess intake of high phosphorus sources such as beef, milk or colas.

I recommend trying supplementing with magnesium malate or citrate first to see if this helps with the muscles.  

Vitamin D can help treat hyperparathyroidism, but it can also increase calcium uptake that can interfere with the magnesium.  This is why I recommend trying the magnesium first.

Not sure about the sore throat and sour taste if the ENT could not find anything.  I would have suspected a throat or sinus infection.

As for the loose stools this could be a number of things as well.  Most cases will pass in a short time.  If it continues then building up your flora with cultured foods and prebiotics would be my first suggestion.  This will help with any infection in the intestines and leaky gut.