I Seem To Be Experiencing Hand, Leg And Feet Cramping

I seem to be experiencing hand, leg and feet cramping with increasing frequency. It use to occur only at night and initially only involved my legs. I now get cramps both day and night (not everyday but frequently) and the cramps now occur in my hands and fingers, feet and toes, legs and even occasionally in my chin (when I yawn.) What can be causing these cramps (which are extremely painful and usually last 10-15 minutes) and are there any proven remedies?