Can a guy be too shy to make a move?

Some people say that if a guy doesn’t make a move such as ask you out he’s not that into you. Other people claim that guys CAN be too shy to ask a girl/woman/lady out.

What do you think?

I personally believe that if a guy IS interested he will always ask the girl out, but I am not so sure now, as I just met this guy who acts very hot and cold.

He gets really nervous when it’s just me and him, and I can tell by the way he looks at me that he likes me, but he hasn’t made a move yet and when we’re with other people he gets stiff and turns his back on me occasionally. (We’re both 27–28 so we’re no teenagers)

Whatcha think? Better to let him come to me or to ask him out myself?