behind the camera is not working why?

I'm sorry to hear that your iPhone 13 Pro's camera is not working. There could be several reasons behind this issue. Here are some troubleshooting steps you can try:

1. Restart your iPhone: Sometimes, a simple restart can resolve temporary software glitches. Press and hold the power button until you see the power off slider. Slide it to power off your device, then turn it back on after a few seconds.
2. Update your iOS: Make sure your iPhone is running the latest iOS version. Go to Settings > General > Software Update to check for any available updates and install them if necessary. Updating the software can often resolve bugs and improve device performance.
3. Check camera restrictions: Go to Settings > Screen Time > Content & Privacy Restrictions > Allowed Apps and ensure that the Camera app is enabled. If it's disabled, toggle it on.
4. Close camera apps running in the background: Double-press the home button (or swipe up from the bottom of the screen on iPhone models without a home button) to open the App Switcher. Swipe left or right to find the Camera app preview and swipe it up or off the screen to close it. Then, relaunch the Camera app.
5. Clear camera cache: Some users have reported that clearing the camera app's cache can help. To do this, go to Settings > General > iPhone Storage, find the Camera app, and tap on it. Then, select "Offload App" or "Delete App." Afterward, reinstall the app from the App Store.
6. Reset camera settings: Go to Settings > General > Reset and select "Reset All Settings." This will reset your device's settings to their default values, but it won't delete your data.

If none of these steps resolve the issue, it's possible that there may be a hardware problem with the camera. In that case, I recommend reaching out to Apple Support or visiting an authorized service center to get further assistance and potentially have your device repaired.