Sperm didn't come when I masturbate, I have some kidney problems

Hello there. I'm new for here.i have a big problem. I am 19 years old.But when i masturbate in there days,sperms didn't come.And also i have a kidney problem .There are two stones in my kidney.one is gone and other one is still there.But i want to know what happend to my sperms.im really scared. Help i hope a quick reply