After painting the walls and ceiling 3 times I have light and dark spots in it can anyone tell me what I did wrong:(

Not sure exactly what you mean here. It would help to have a little more information and explanation. If you have moved lighting objects around in a room in order to accommodate the painting, then that would affect your perspective of the painting when you turn the lighting objects on after you have painted.

What was the sheen of the paint that you were using? (Flat, satin, semi-gloss or gloss?)

Was all of the surface areas that you painted thoroughly dry when you thought that there were light and dark spots in it. If it is a textured surface, then it is going to take longer to dry, no matter what kind of paint it is that you used.

Did you prime it, if you did any sheetrock repair or mud, and didn't prime those areas this will cause that