Q: iMessage using my email not my phone number HELP

Does anyone else have this problem and if so what is the solution?  I have an iPhone 6 and when I turn on iMessages it activates; uses my phone number then switches to my Apple ID; which is an email address.  HOW do I get it to just use my phone number?

There is a section called "send and Receive" and it has my phone number and my email address checked. but the phone number is "grayed". I try and delete the email address and it will not allow it to be removed.

Also in that section  "start new conversations from": my phone # is checked -- however it sends from my email.