 This phase I trial studies the side effects and best dose of stereotactic body radiation therapy in treating patients with head and neck cancer that has spread from where it started to nearby tissue or lymph nodes and is at high risk for continuing to spread because the patient cannot undergo standard chemotherapy. Stereotactic body radiation therapy is a specialized radiation therapy that delivers radiation directly to the tumor in smaller doses over several days, which may kill more tumor cells and cause less damage to normal tissue. 