Hello there, Chris.
The following Knowledge Base article offers up some great information that is relevant for troubleshooting the issue you're describing:
iOS: Troubleshooting Messages
http://support.apple.com/kb/ts2755
In particular the following section should prove helpful:
- Go to Settings > Messages > Send & Receive on each iOS device and make sure that you signed in with your Apple ID. You must use the same Apple ID on each device.
- Go to Settings > Messages > Send & Receive > You Can Be Reached By iMessage At and make sure that you selected each phone number and email address you want to use with iMessage.
- If you linked a phone number to your Apple ID with iMessage and the phone number hasn't appeared, followthese steps.
- Sign out of your Apple ID in Settings > Messages > Send & Receive and Settings > FaceTime on all devices.
- If you're linking a phone number to an Apple ID, sign in to iMessage on your iPhone first. Then sign in to the rest of your device one by one with iMessage and FaceTime.
Thanks for reaching out to Apple Support Communities.
Cheers,
Pedro.