I have a hard bone like lump about the size of a dime near the left occipital. Have eczema on my scalp and it has been inflamed recently. What is it?

It's a lymph node. Considering that you have eczema on your scalp, it is most likely a lymph node that got stimulated to enlarge. You can tell that it is not a bone by trying to move it under the skin. If it moves, it is not a bone. If your eczema is infected, the lymph node will stay enlarged, i would suggest that you have a doctor take a look.
LYMPHADENITIS. Any infection in the scalp drains to the node which becomes swollen and tender.