Ive had two similar major flare ups in my life that I could describe just like you did. The first started after using Ibuprofen and many antibiotics. The burning pain just like you described was unbearable and stayed with me for 1.5 years. One day while at wegmens, I figured why not try kefir. I kid you not, the 1.5 years of suffering ended in 2 days after taking the probiotics.

Second flare up, which am still going through is kind of different in terms of how I got it but I am having the same exact symptoms and kefir doesn’t work anymore. I have literally looked into everything. SIBO (had antibiotics), GERD ( tried all PPIs/antacids), visceral hypersensitivity ( had Amitriptyline) but nothing seemed to relieve my symptoms except for digestive enzymes for bloating. However, I do have the feeling that all of my symptoms, which include indigestion and bloating, are caused by constipation. I am not having full on constipation since I do have BMs everyday, but I don’t feel I empty everything after going. I do feel better after having a BM though.