Didn’t the guy with the lump on the back of his head say he had his yearly checkup and his doctor didn’t even notice it (because he didn’t turn around) ? Gee when I have my checkup my dr puts his stethoscope on my back in several places and has me breathe in and out and in and out, and would definitely have seen it. Even a dr looking in your ears could see a lump that size on the back of your head.