I am so sorry that you have to go through this torture... But what you need to do is get your neck and throat checked out by a medical professional, get a CT scan and a PET scan and simply as an addition get an endoscopic test.... I bet you are fine... But somehow it seems that you have convinced yourself to have this dreaded disease... You maybe suffering through hypochondriasis, maybe...
But still get an appointment fixed with an oncologist, ENT , otolaryngologist asap...