As previously posted, magnesium deficiency is probably the problem.
I get them in my legs at night and they feel like someone is squeezing my leg in a vise and applying an electrical shock at the same time. Then I hop around praying for them to stop, but when I start back to taking magnesium and drinking plenty of water the spasms stop.
For you it could be as simple as drinking plenty of water just to see if it works.
Thanks
Sonny