I have very sensitive mouth tissues in general & can't even tolerate most toothpastes because they burn the crap out of me. I have healthy gums & was seeing a periodontist for an implant to a tooth I lost in an accident. Anyway, I started using a Water Pick to floss without as much pain & to have the added benefit of toughening up my gums. Well, it's worked! I had to start at the lowest setting & gradually increase, but the periodontist is impressed & I have less trouble! Now, I still have to be careful of my chemical sensitivities, but the physical irritants such as popcorn & crusty bread, are much less bothersome. It took me several months to get to this point, but it was worth it, it's easy peasy to do & I can even manually floss with no trouble. I would say, at the least, it's worth a shot, if you're interested.
My first advice though, would be to get checked out by a periodontist to make sure there is no underlying cause that you, or a dentist, just can't see. They might have some recommendations for you. Mine said trying the Water Pick wouldn't hurt, as long as I NEVER use the highest setting! He said no one should ever use the highest setting!
I wonder if you use products that are already starting an inflammation response & then the food is exacerbating it? I know a person who was using Listerine on a toothbrush to do a final brush through, she couldn't tolerate an actual rinse, it was too strong, but thought she would benefit her gums to still use it in some way. Well, for a year, she thought she could no longer eat anything with tomato, citrus, & several other foods. She thought it was because she is older, 83 & that was just part of aging. Well, she ran out & wasn't able to use the Listerine for a month or so. Guess what, the longer she went without it, the better her mouth got & it took her a while to link the cause to the symptoms. So, even though the Listerine didn't hurt her or cause noticeable problems to her, it still was sensitizing her to things she used to tolerate well. Just a thought!
I hope you find a solution to this, eating should be a pleasure!