I noticed a few months back a large mass on the back of my neck at the bottom right above the bone on the line of my spine. When I lean my head back back it sticks out and and is solid but not hard and can push in. It doesn't necessarily hurt, but it feel like it will if i push in harder and i notice my neck gets real stiff and its almost like its tired. Its really hard to explain, i was just unsure if its something I never noticed and i'm just freaking myself out or if it should be treated and looked at. Thank you !