back camera shaking

ok so I got a phone. I've never dropped the phone. there's no scratches or crack but every time I use any camera on my phone and I use the back camera it tends to shake very fast and make glitchy noises. I don't know what's wrong with it. I used others apps like snapchat and instagram and the back camera does the same thing. so I think it is my phone and not any of the apps because the back camera doesn't work for anything. please tell me what really going on