What Causes Shaking In The Thigh While Bending Knee?

wens, thursday playing soccer.. it hurt to kick the ball in my front thigh, quad. Friday i went to kick a ball without warming up and got a sharp deep burning pain in my front thigh. It was the worst ever! Then i could barly walk on it and when i did pain shot down the side of my knee.. i continued to play everytime i hit the ball it stung. i limped around the rest of the day sucking it up... very sore still.. when i sit on couch i can not lift my thigh off the couch.. my whole thigh shakes when i bend my knee.. what should i do!? i have allstars cheerleading tryouts monday - friday this week...help please