You have set up your camera but always accidently move it. One way is to lock it. Unfortunately you can disable your camera in the outliner. The position of the camera can still move around if your in the camera view.

1. Select your viewing camera and press N to bring up the side panel.2. Click on the Item tab you see the Location, Rotation and Scale field. Next to these parameters you click on the Open Lock icon, this will switch to a Locked icon, hence locking your camera Location, Rotation and Scale.

If you need to save multiple camera position you could assign a key frame to those fields by right clicking and selecting [...]