<s>[INST] I m 18 and have a lump on the back of my head. I didn t hit my head though. It s the size of a dime and hurts like a bruise but also hurts my whole head like an underlying head ache. The bump is about an inch to the right of my spine where my skull and neck meet. The bump is rather hard and can move a little when I touch it. Please help. [/INST] Hi. Thanks for your query and an elucidated history. The lump as you described can be due to neurofibroma as it is causing so much pain or a lipoma or a sebaceous cyst pressing on a nerve causing pain. The movement suggests that it is not fixed and not from the bone. Get a physical examination done by a Surgeon and get this removed for 2 reasons 1. You get rid of the swelling / disease2. You get a correct diagnosis. </s>