did you roll this on? Did you use a paint from a home center? What knap roller did you use? Did you use a quality roller or brush?
This often happens on ceilings. There is a special tech when using a roller and roll marks will occur if you do not implement them.
If you rolled on, you need to use a paint that sells for about $20 or more a gallon. Then you need a good 1/2 or 3/4 knap roller cover. I personaly like the 1/2.
You roll on a square section at a time and here is the biggest problem area. If you have a wet soaked roller and work one area and work the areas around it. the paint becomes less thick at the end of that run unless you smooth it out properly.
I apply my wet roller on the ceiling and work a 4 foot section at a time and first make a sweeping W. Then i smooth out the area where the w was made and ensure that the paint is on the same thickness within this four foot square area. Then move on to the next. Another concern is always work on the wet side moving to the right. If the paint has a slight chance of drying on one end and you apply another area adjacent to it, the dry and wet mark area will have different shades.
Ceilings need to be painted twice the first time from left to right and the second time from left to right. Then after drying you always have to touch up. When touching up, patch that area in a square and feather it out.
Many people think that rolling out a wall or ceiling is a piece of cake, but after drying you will see your lap marks show up.