What Causes Vibration Feeling In The Legs?

Hi, may I answer your health queries right now ? Please type your query here...At times, I feel pressure like I am in a vice; then legs begin to have strong vibrations up to my waist; lasts about 20 to 30 seconds. Go days without this problem, then it occures again. Last night while trying to sleep, I had probably 12 to 15 of these episodes; like seizures.