I have mounds of soil in lawn, I think it is worms. Could it be anything else?
Yes, it is likely earthworms. You usually want to keep the worms- they are very good for the soil. There are not any products that can get rid of them either.
Knock down the casting and spread them around with your garden tractor and a piece of chain link fence dragging behind it. If there are uneven places in the lawn, you can get a ballast roller, fill it ½ full, and roll it over the soil to even out the areas.