Mirtazapine/remeron has improved some of my symptoms such as a burning throat after eating/drinking anything. is there a reason for this?

Yes: Antagonism of the 5-ht3 receptor, an action Mirtazapine shares with the approved antiemetic ondansetron, significantly improves pre-existing symptoms of nausea, vomiting, diarrhea and irritable bowel syndrome in afflicted individuals.[97] Mirtazapine may be used as an inexpensive antiemetic alternative to ondansetron. En.Wikipedia.Org/wiki/mirtazapine it is likely that it is having an antacid effect.Be careful because Cimetidine can increase Mirtazapine blood levels. Please discuss that with your physician.