Are these drywall blisters normal settling, or is there something wrong?
Do the wall bumps occur in regular intervals? If that's the case, it could be popped nails. If there is a pattern to it, open up the drywall at one of these bumps to see if there is a nail.

Sometimes in older houses, especially if the drywall was nailed (instead of screwed) into the studs and the structure has been working a lot, the nails can "pop", which means they work themselves out beyond the surface of the wall. You can fix this easily by finding the studs, screwing the drywall onto the studs above and below the popped nail (like 2-3 inches away). Then, remove the bumpy material around the popped nail and drive the nail below the surface with a nail set. Finally, patch with joint compound and sand/paint to cover everything up. 

Here is a good guide with pictures. This article gets all philosphical about it if you care. Google drywall popped nails to confirm via image search whether this is what you're seeing (scale is hard to tell from your pictures, so you'll be a better judge of it).

This could apply to the walls, and maybe the ceiling, but I've personally only encountered in walls in my place, so I can't say for sure whether your ceiling situation may have a different origin and requires a different fix.

In any case, drywall issues can usually be fixed easily, as long as you have a joint knife, drywall screws, joint compound, and sand paper handy.