I have a small bump on the back of my neck close to my ear its right umder the knobss on the back of your head its a lil sore but u can't see anything?

Probably lymph node. There are several lymph glands located within the structures of the neck & will vary in size from the size of a pea to much larger if stimulated.When stimulated they can enlarge quickly and feel tender to touch or compression. A visit with your dr during regular hours should separate the simple transient issues from those needing further tests.