Testical Cancer

I have a small bump on inside my testical. It is pea size and very dense and smooth. It enlarges with blood flow to the area. I check it every morning and it hasn't increased in size. It is fairly small in the morning and would be hard for a doctor to find. It is internal to the testical but right under the testical skin. (i.e. it is not an exterior bump). Can someone describe what testical cancer feels like ?