Hi there I ve read your query and understand your concern. I would like to tell you , you already have seen a neurologist for headache and stiff neck. He would have told you if there would have been something wrong. First stop thinking about the brain tumor, thinking about the disease gives you stress and ultimately results in headache. Look for the possibilities than can cause you neck stiffness, like kind of your work, your sitting posture, any sports injury or back injury. It s advisable to personally consult with a orthopeditian to rule out the possibilities of degenerative disc disease. Neck stiffness generally heals itself within a period of a week. But for better improvement you can try some home remedies like -hot or cold pack application over the affected area -Gental massage will stimulate blood supply and early relief from symptoms -you can take pain killer like ibruphan SOS Hopefully I answered all your queries Wish You Good Luck