What Is Causing A Persistent Twitch In My Leg Below The Knee?

Hi, I was at work a couple of hours ago and felt a sudden pulsating feeling in my femur area of my leg, a few inches below me knee. It did it every few seconds and is still doing it to a lesser degree. (After some muscle cream) I stand, lift, and squat all day so everyone is suggesting a muscle cramp or pulled muscle. I just want to know if it could be something more serious. Again, it's not my calf. It's the front of the leg. A pulsating twitch.