Last year, my husband started having stomach pains, constipation, bloating and discomfort. He went through a battery of tests, ultrasound, endoscopy, barium swallow, h pylori tests, x rays, even a test for Zollingers. All came up negative. He also had an occasional sore throat. The stomach pains seemed to be slightly relieved when in an upright, slightly forward position. He was prescribed Prevacid and took it for about 9 months. He has been mostly symptom free since then...about 9 months now.
To this day, he still hasn't been diagnosed. Although the Gastro never said it, I'm thinking it's IBS. I think stress has a lot to do with it as he was quite stressed out during that time.
Take Care. I hope you feel better soon.