Can someone get my number from my iphone email?

Someone keeps sending me unwanted messages, and I have no idea how they were able to find my number. My number is relatively new, and it's absolutely nowhere to be found (I'm extremely careful about personal info)..at least that I know of. The only connection I have with this person is that they know my email address, and I use the same email as the primary email on my iphone. We don't have any acquaintances in common that could've shared my number. It's driving me nuts..I'm wondering if there is an app or a software program that somehow lets people send text messages directly to someone's iphone through their email address. I have no idea how else this can happen.

Any ideas?

Thanks in advance!