I linked an iPod to my main Apple account and now the texts and FaceTimes received on the iPod come to my phone as well. How do I fix this?

Settings>Messages>Send and Receive and remove the checkmarks by everything but the telephone number.

I'm sorry, didn't realize I didn't say. That needs to be done on the phone. You can check the iPod to make sure the phone number is not listed there, but it shouldn't be. If it is, remove it from the iPod, remove the Apple ID from the iPhone.