ok health questions serious answers?!

well when i go to lay down in my bed at night like my calfs or my leg idk wich one those like a twitch not like a twithc more like if i feel the veins pulse anyways my doctor said its because before i go to bed im sitting down on my pc and my legs are on the bottom of my desk so anyways could this be als im 18 healthy male theirs no one in my family with this anyways its like a pulse or twitch dont know wich and then it goes away it those not hurt so is this als.