I have a hard testicle, however AFP levels are normal as well as blood work, the doctor suspected hernia, what should I do?

What's on imaging? I'll bet you infarcted it from a hernia or old torsion and didn't realize it. An imaging study is worth doing to be sure it's not tumor -- but testicular CA is almost never "hard". You're free to request a sperm check to see if you can be a dad. Best wishes.