When you have stage fright, your body is subjected to the effects of the fight or flight response. As the fear of performing takes over, this fear triggers the stress response, which prepares the body to either fight the danger, flee from the danger, or freeze. Your body responds by tightening up the muscles, forming a "lump" in the throat, developing "butterflies" in the stomach, buckling of the knees, sweating, trembling, increasing the heart beat, and increasing the rate of breathing. All these changes in the body makes it even more difficult to perform in front of an audience.
