Sorry to hear of your problems. You're still early in the recovery phase. I really couldn't eat until 3 months post treatment, and that was very very little, and it really took much longer to what I considered being a meal, maybe 8 months on Thanksgiving. Small steps is best, and in this case, time heals all wounds. I'm two years out my first post rad treatment, I had several recurrences, treatments, but can eat everything now, probably more than most, and had, and still do, have a peg tube, which I don't use now after my last treatment in November, but is my back up for several reasons. Do you see a speech and swallow therapist, do the exercises?

Try to sleep on an incline, use a humidifier, drink water before sleeping, and have some available table side. Water only relives the dry mouth for 16 minutes. Milk replicates saliva and coats the mouth, if you want to try that.

Maybe spraying the food with vegetable oil, I used olive oil in the past, to coat the food to help swallow.

As far as pain, idk if you are taking pain meds, if not see about that, and meds for choking.

Good luck