I have a small pea sized lump on the bone behind my ear, should i be concerned? should i watch and wait to see if it enlarges or have it evaluated now?

Probably a reactive lymph node, watch it for now, do not touch it frequently. You only see doctor if it gets bigger in a short time, days or weeks. It will get smaller by time but it may stay there for a long time.

You may feel the lump/node every couple of weeks, if the lymph glands doubles in size, becomes painful, ulcerates, or other nodes become enlarged, or you develop fever, or lose weight, you should see a doctor. Wish you good health!