Took an Arabien, went to bed, and could not go to sleep, because there's one more thing I felt like I should talk to you about.
The reflux. If your gastroenterolgist did the endoscopy and did not biopsy your esophagus and stomach area, they cannot determine just by looking, whether or not inflammation is there, FACT IS, it may look okay to the visible eye, doesn't mean it is.
But if a biopsy was done and no inflammation exists, I don't think I'd worry too much about acid reflux being an issue. Too much acid production in turn causes irritation to your esophagus, stomach, and even possibly your throat.
But where your ENT looked down in your throat and obviously saw a problem visible to him, something had to of been wrong there. With the types of problems you have with your sinuses/allergies/post-nasal drip, it could cause that irritation and be the cause of what is bringing on the spasm in your throat. The anti-spasmotic or muscle relaxants could very well make that problem go away but whatever is causing the irritation down in your throat neeRAB treated. CorticosteroiRAB may be a good option to try. One of those little suckers can make the worst sore throat vanish in a days time. I've tried allergy, sinus meRAB myself, nasal sprays: flonase, nasonex, etc, with only temporary help from them, might work a few weeks then nothing. You might just need something that will help clear up the inflammation down in your throat & dry up that mucus production, if possible, because inflammation is a hard one to battle and get rid of completely. Maybe you should ask your ENT about doing a biospy where he saw those problems down in your throat. It could clear up the question of what's wrong. Goodnite.