My android phone cannot recognize my camera

How come my android phone cannot open my camera? I do have the system app on my phone, but I find it in the Apps portion and no matter what kind of camera app or camera repair app, it will not work. One app asked if the camera was in use. I cannot press the lock button with the volume down because my volume down button is stuck and broken. I tried downloaded the camera repair apps like Camera (CMMFix) for Cyanogenmod and it doesn't work. My phone was just fresh from factory reset. Also I get random crashes like camera and imageview has stopped working randomly.