It could be anthing from an infection to cancer. You need to find a free clinic in your area and get checked out. A doctor can exaime you when you go and give you a definative answer, unlike people on the internet who can't see what's going on.
What you are descirbing sounds like testicular tortion. Have you had any trauma in the past 6 years? You need to see a doctor, even if it's not testicular tortion. If you don't, you could possibly lose a testicle.
You could have done a variety of things from ruptured your urethra to "broken" your penis. If it burns when you urinate, blood comes out in your urine, or you cannot urinate at all: see a doctor. Even if none of the above have happened, you should still see a doctor to make sure there is no permanent damage.
