For more than a year, Arthur L. Kimbrough had done everything he could think of to find out what was causing the stabbing sensation that radiated from his throat to his neck and down his left shoulder. He had seen anesthesiologists, an ear, nose and throat doctor, a neurologist and neurosurgeons in Florida and Maryland; undergone tests and scans; and taken a variety of drugs that failed to alleviate the intensifying pain that baffled his doctors.