Camera shows ghost lighting or refrective image
This lens flare is due to the geometry of the camera and the physical aperture / focus ring and might be normal or might be signs that the internals have shifted or become damaged. A hard drop can knock the camera out of alignment and cause this. Also, there are lighting conditions that guarantee a properly assembled and working iPhone camera makes that flare. 


Take controlled photos with other devices if you wish to rule out that it's just the natural result of that light bouncing off the camera. Get a lens hood or change the exposure is how photographers manage this (this problem is just one of optics and sensors) if it turns out your device is working like others.
Take the phone (camera) in for service if you believe it's not working as designed and you can't see any signs of physical damage or a drop. If the phone isn't up to spec - Apple or their service team will offer a repair under warranty assuming you're covered. The only thing I would expect to pay is if I damaged it (warranty doesn't cover drops or breaks).