Why does a guy text me hey and when I text back he doesn t say anything?

He is probably just nervous and doesn't know what else to say besides hey. Maybe he is toying with himself and getting the nerve to talk to you, then backing down.
Or, he could be a complete idiot with nothing else to do. but i doubt its the latter. Good luck

Seems like he's a f***boy to see how many girls will respond. Try saying "hey" to him first next time and when he replies, don't. He'll get the hint

He's just doing it to make sure he's "got" you, if that makes sense. Just don't reply at all and see him freak out.

stop sending messages like hi grandma is your tv fine?