That's lens flare and completely normal. Before you take a picture, you can see the dots (which are reflections of light against the camera sensor) and you can alter the angle of the camera a bit to eliminate the flare. Even $100,000 cameras do this. And it's most noticeable when using night mode photography.
Here is an example of a photo I purposely took with lens flare and without changing my position I repositioned the camera relative to the flare to eliminate them completely:
I didn't move, but moved the angle of the camera and voila, flares gones: