Why wont my iPhone 11 stop glitching?

Try the following steps:

1. Restart your iPhone. 📲
2. Make sure that your screen is clean and free of any debris or water.
3. Disconnect any Lightning or USB-C accessories. If your screen works after removing an accessory, try using a different outlet, cable, or charger.
4. Remove any cases or screen protectors.

If part of your screen doesn't respond, responds intermittently, or responds even when it's not touched, contact Apple Support.

If your screen is cracked or shattered

Call Apple Support at 1-800-APLCARE.

▷ Contact Apple Support. 

I am not sure what exactly do you mean by "Glitching". Can you provide some details?

Meanwhile, Try and Force Restart your iPhone EXACTLY as shown below and see whether that resolves the issue:

• Press and quickly release Volume UP button
• Press and quickly release Volume DOWN button
• Press and Hold the SIDE button until an Apple logo appears and then release the Side button (Can take up to 20 seconds. (DO NOT release Side Button when invited to Slide Power OFF). 

Axel F.