2. Constant Headaches

"If you are experiencing headaches that are out of the ordinary — in that they are more severe and painful than you can handle —you should probably have it checked out," says Dr. Mia Finkelston, A Board Certified Family Physician who sees patients LiveHealth Online, over email. "This type of headache can be caused by an infection in the central nervous system or it can be caused by a hemorrhage or bleeding in the brain."