I'm Experiencing A Leg Pain Which Seems To Emanate From

I'm experiencing a leg pain which seems to emanate from below right knee in my calf muscle. I noticed this after sitting at my desk for about an hour. Increased to very uncomfortable level, persisted for over last hour has since subsided about 50%. Pain extends to foot; overall if feels like a real bad cramp without having done any strenuous movement. Not comfortable in any position, taking weight off leg didn't make any difference. I waited until I felt confident that I could drive myself home. Took 3@ 81mg aspirin with glass of water,min 30 minutes time pain subsided slightly