I was recently diagnosed with "Doxycycline Induced Esophageal Ulcer". I had been on the antibiotic for about 7 days and was never told NOT to take it before lying down. I usually took it at 8 am and 8 pm, but I forgot to take it one night and took it right before I went to bed at about 11. It didn't enter my stomach but sat at the edge of the opening to the stomach in the esophagus and literally burned it. I now have a terrible ulcer, have had to go on expensive medication, cannot eat anything - only liquids that I can tolerate (The doctor said, "if you wouldn't pour it on an open sore, don't swallow it"!). It can take a couple of months to heal. I am miserable.
Apparently taking ANY pill and then lying down is not good. I wonder about people who need sleeping pills?? Anyway, have you taken any pills lately that were big or different or did you take one at bedtime that could have gotten stuck?? The pain is horrible and I am hoping it heals soon, but please see a gastroenterologist to diagnose you because the sooner it gets treatment the better.
I hope you feel better soon.