Welcome to Android Central! Does this persist in Safe Mode? On most Android devices, while powered on, press and hold Power until the Power Off menu appears. Press and hold the Power Off selection until the Safe Mode prompt appears. Tap OK.
If it goes away in Safe Mode, then some app you installed is inappropriately keeping the camera occupied. Look through your apps to see which ones have Camera permissions, and start uninstalling them one by one until the problem goes away.