Hey lilappleuser26,
We'd be happy to help out. Sounds like you have screen orientation lock enabled. To disable this, swipe down from the top-right corner of your iPhone 13 and tap on the screen orientation lock button just below where you enable/disable your data connections (Bluetooth, Wi-Fi, etc.)
For more info, check out the following steps, as they're best equipped to assist:
Rotate the screen on an iPhone without a Home button
1. Swipe down from the top-right corner of your screen to open Control Center.
2. Tap the Portrait Orientation Lock button
to make sure that it's off.
3. Turn your iPhone sideways.
This info comes from: Rotate the screen on your iPhone or iPod touch - Apple Support
We hope this helps out.
Take care!