About four or five days ago I noticed a bump just above the shaft of my penis on my abdomen. It is about 1- 1 and 1/2 centimeters across, half a centimeter long, and feels to be about 1/2 a centimeter thick. It is very hard and when pressed on it causes some discomfort. Pressing hard causes a sharp pain. Being aroused and having the weight of the penis on it hurts sharply. I can not seem to move it. Is it anything that I should be worried about? I am twenty years old. I have never had sex unprotected or with anyone who was not a virgin.