MY BUMP IN MY HEAD!!!?!

ok so i have noticed that there is an indent in the back of my head, and as long as ive known myself, i've never gotten sarcasm or jokes of any sort, and apparently this is true with my friend too. Could this bump be the reason i don't get anything? like is it blocking out the sarcasm part of my brain? THANK YOU :) and please dont post mean answers this is a legitimate question :)) OK THANK YOU AGAIN :)