Testicular cyst? please help!!?

I have a small bump on the very top of my testicle, it feels sort of hard, and it moves around.. it does not move a whole lot but it def. moves. sometimes it feels like it isnt connected to the actual testicle.. sometimes it does. I have gone to the doctor twice and he said it wasnt anything, and i even had a catscan done and they said everything looked fine..does this sound like a testicular cyst? thanks