The system says that you have requested a new expert.
I am sorry that you are having so many problems, and while there are no easy or direct solutions to your symptoms, I have a couple of comments that may be able to help.
There are also a couple of other medicines that can be considered for relief of the pain, including carbamazepine (another type of anticonvulsant) or duloxetine (another type of antidepressant). Since the carbamazepine is in a different class than the gabapentin and the duloxetine is in a different class than the amitriptyline, these other medicines may work when the previous medicines did not. Each of these medicines can relieve chronic pain from a variety of different causes, so may help even when the specific cause is difficult to determine.
There is an option to clarify whether this pain is related to the glossopharyngeal nerve, which is to perform a nerve block of that nerve. An initial injection with numbing medicine can determine whether the symptoms are relieved, and if so, a longer acting block can be considered, such as with phenol or alcohol. These injections are usually done by anesthesiologists, including anesthesiologists that specialize in pain management injections.
If numbing medicines relieve the pain, but the nerve block is unsuccessful, then surgery on the glossopharyngeal nerve may be considered, such as a neurotomy.
If I can provide any clarification, please let me know.