Could be muscle spasms. If I was you I'd pick up some magnesium chloride solution from a pharmacist and take the required loading dose for a bout a week and maintainance doses thereafter. For more on this Sherry Rogers MD goes into detail in some of her books about magnesium deficiency and how to treat it. Muscle spasms/cramping are main symptoms og magnesium deficiency however, at times, it can be an electrolyte imbalance as well. The magnesium loading is the easiest thing to first try.