Imessage only works with email

My phone number is not registered with imessage, It says "waiting for activation" but it's been saying that for a while now. I can still send messages it but it sends them as my email and when i click " send & receive" the only option is my email, it does not show my phone number as an an option. How can i change that? i"ve restarted my phone, I've reset my network settings and everything but nothing works.