I am getting referred pain in my left side during sex. i am a man.?

Probably muscle spas: If you are a healthy man with no illnesses and experience pain in your side during sex, you are having a muscle spasm.

Testicular problem?: If pain occurs only during sex, then possibly testicular problem. For a problem like this, you need a physical exam by a physician, who can also obtain a more thorough history about the problem to help determine what it is and whether or not it is serious.