Hi rspdallas,
The first thing to double-check is that your notification settings for Messages are configured properly. Change message notifications on iPhone reviews the available options that should be confirmed:
- "Turn Allow Notifications and immediate delivery for Time Sensitive Notifications on or off.
- Set the position, locations, style, and sounds for alerts.
- Choose when message previews should appear on the Lock Screen, and how they should be grouped.
- Set how many times to repeat an alert (from Never to 10 Times) below Customize Notifications.
See Change notification settings on iPhone."
Then, confirm you have not scheduled a notification summary as described at View and respond to notifications on iPhone and that you do not have a Focus enabled per Use Focus on your iPhone or iPad. Another element to check is that the Ring/Silence switch has not been changed. How to put your iPhone on vibrate, ring, or silent mode illustrates how to confirm this.
If all of those are correct, working with AppleCare directly via Apple Support may be necessary.
Regards.