Swollen Testicle-Cancer?

I'm a 22 year old male. For as long as I can remember, my right testicle has been almost two times larger than my left one. I know that I had surgery for a hernia when I was born. I believe it was the left testicle however. From time to time, the enlarged right testicle became painful and began to pull up inside my body. This usually happened when I was working (no heavy lifting). About a month ago, I woke up with intense pain in my abdomen; the right testicle had drifted up really far in my sleep. The next day, I felt whatever it is down there loosen up and my testicle returned to normal (and by normal, I mean enlarged, but in the right place). The pain ended immediately. I've been reading about the possible causes of an enlarged teste and I'm very scared that it could be cancer. And since I've had this condition for so long, I'm afraid that if it were cancer, it's been there for so long. I'm going to make a doctor appointment soon, but until then, is there any information someone can give me?