Do I have testicular cancer?

I am 23 years old of athletic build. I was always told while younger if I feel any peanut shaped lumps that it could be cancer. Are these 'lumps' extended off of my testicles or is it just a lump inside my ? What is the significance of the 'turn your head and cough'. I can't see any reasoning for that. The lump I have is hard and peanut shaped/sized. It is on the upper left of my testicle. It feels more like a group of hardened skin.