You could have tried lifting something too heavy for you.
My son is 13 and he sed his ball hurt him I have had a look an carnt see anything .it is the right one that hurts he wont let me feel coss it hurts when I touch them .
If your hitting puberty thats normal
They could be growing but if it don't get better go to a dr.
Well you could have hit them while playing sports or something.
Maybe its because you got a bonner and you didint came
I don't know but , my balls have been hurting for 3 days and I never got hit there but I've been having back pain with it to..the pain I'm having is from my hip to the back..so you might have Fibromyalgia.