Wall studs show through paint
In any event, if it really is the STUDS that are showing through the wall, then consider slapping up brand new drywall on top of your current wall. It probably just is not a very good quality wall. Mark the location of the studs on the floor and ceiling so you can nail or screw the panels to the studs with long screws/nails. You can use thin pieces of drywall because you will be covering an existing wall, which will reduce the heavy lifting. It takes about the same amount of time as painting, and the finished product will be far, far, far better than painting an uneven wall.