Hi Asikka,
Thanks for using the Apple Support Communities!
I understand that in Settings > Messages > iMessage > Send and Receive, you are not seeing your phone number listed. To troubleshoot this situation, I would recommend following the steps located in the following article. I know the section that I am quoting is written for iPad and iPod touch, but the same steps should be helpful on your iPhone.
If your phone number is missing on your iPad or iPod touch
Sign out of iMessage and FaceTime on all of your iOS devices:
- Go to Settings > Messages > Send & Receive. Tap your Apple ID, then tap Sign Out.
- Go to Settings > FaceTime. Tap your Apple ID, then tap Sign Out.
Sign back in to iMessage and FaceTime on all of your iOS devices:
- Go to Settings > Messages > Send & Receive. Tap Use your Apple ID for iMessage. Then sign back in with your Apple ID.
- Go to Settings > FaceTime. Tap Use your Apple ID for FaceTime. Then sign back in with your Apple ID.
Link your iPhone number and Apple ID to use iMessage and FaceTime - Apple Support
Best!