Is this going somewhere?

There's a guy I work with. I KNOW he likes me. He comes to my desk and talks to me for hours at a time, teases me, jokes about other guys in the office "liking" me to see my reaction, always pops in to join a conversation when someone else is chatting with me, tells me something he does and how I was the first thing that popped into his head, flirts with me. Etc. At this time we only communicate through email. Which is fine, we work together and I'm enjoying the easy going fun flirty butterflies in my stomach day to day of him and work. The problem is, I'm more outgoing and I fear that it will push him away. Like I might come off aggressive or needy. He always responds to my emails, but NEVER sends ME one to start. So I read into that. He's told me that he didn't know what to say sometimes so he doesn't respond. Since I know we can talk for hours face to face I know that it is his preference isn't email but actual conversation, which is great. But I'm constantly left with this need to continue our connection after work with SOMETHING and find myself always hoping that he sends me anything and I going crazy. Please help.
Is this going somewhere?
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