Sounds like you need to work on your running action.
If your head is bobbing up and down enough to bump ear plugs out you're pushing upwards to much with your legs, you'll also be landing too hard, try to modify your action to use that up energy to push yourself forwards. Your head shouldn't move up and down.
Try adding some soft sand running, that'll teach you to run softly, if you are landing too hard in sand it makes it hard work as you just keep digging holes.
Vibram five fingers are good to soften running styles as well, you'll feel it if you're landing hard or heal striking. They take a bit of getting used to, you'll be sore for a few weeks until your feet and legs toughen up and you change your running style to soften the landings.