I have been got a black dot on my penis behind the head of my penis what is it, it doesn't hurt or cause any pain, is it anything to be worried about?

We really can't tell you. You'll have to see a doctor.

It could be nothing, it could be something, only a doctor can tell you for sure.

Don't leave your reproductive health up to people on the internet. No one can diagnose you, even a doctor, without seeing the dot and without doing tests.

Good luck.