My Right Leg Shakes Randomly And Uncontrollably The Only Way

My right leg shakes randomly and uncontrollably the only way to stop it is to pinch my Achilles or press really hard into the back of my knee or move my leg or toes continuously but as soon as I stop moving it starts again. This has been happening for over a year now. I've recently been getting severe headaches when doing strenuous activities. What could this be?