Small Bump, possibly pimple underneath skin ontop of right testicle

I am 14 years old and recently, I discovered a sharp pain in my right testicle. Just now I told my mom who had breast cancer before and is pretty experienced with cancer enough to tell me that it was not cancer, which made me feel alot better.She told me its a sort of pimple that can grow on the testicle. Is that true, I dont really know what to believe.