Is there a product to fill in popcorn ceilings. Do not want to remove because of cost related to asbestos.

There is a product available at stores like Home Depot and Lowe's that you'll find in the paint department that comes in an aerosol can. If you have just a few small areas that need fixing (and I mean small), toothpaste works! Just squeeze it on and work it with your fingers until it looks like the surrounding texture. I don't know if it's paintable, though.

I want to clean and repaint my popcorn ceiling how do I go about it

You can get a wet dry vac with a brush attachment on it and vacume the ceiling. Paint the ceiling with ceiling paint using a roller that has a lot of nap to it. You can paint it with a semigloss or eggshell also and you won't have as many problems with it falling off when you try to clean it again.