largish bumps on and around my left teste

im 15 years old and around 18 months ago i noticed in the shower that my left teste was bumpy. recently i have noticed that wheever i am standing for an extended period of time and they can hang loose like in sports or in the shower, it is super bumpy. i dont know whats wrong. it was hurting one day in basketball practice and i felt around in the toilet and it was really lumpy. when i was in the shower and i could take a good look it looked like the himalayas down there and my left ball is considerably larger than my right one. i have been worried sick because it could be cancer which would be the worst thing imaginable that could happen to me in my life. i really need some help from anyone who knows