Beth,if you understand why you have the cracks, you will have a better understanding of what to do about them. The cracks are a sign that something is moving or has moved. And it's the same thing with mail pops, but water can be more directly involved in these also.
Sometimes, the place to fix cracks in your walls is by fixing the drainage around your house, or stiffening the floor joists or similar fixes that work because you stop the movement that is making the cracks in the paint, plaster or drywall. Since the potential problem areas are so many, it's impossible to list all of them here, but you might take a walk around your place, including the basement and attic, to really look for something going on.
One other possibility is that your drywall work changed the stress patterns or that other repairs, recently or years ago, did. Since these cracks might be quite old, keep that in mind also.
There are solutions to repair really bad walls, like the fiber mesh paper, but nothing will really stop movement generated cracks and other damage until you stop or slow the movement.