I have severe reflux and IBS (don't know if they're actually related or not). My reflux has continued to progressively worse over the years. I've been on PPIs for about 7 years now. I supplement with 300 mg of zantac every night. I also have to elevate my bed before lying down. I get an upper endoscopy done every couple of years to look for Barrett's, but so far I've not had any signs. I do, however, always have erosive gastritis and erosive esophagitis, which causes Barrett's.
As someone already pointed out, reflux is commonly associated with certain AI diseases (e.g., SSc, MCTD). I currently have dx RA, but my sx are leading towards either MCTD or SSc.
My GI doctor told me once that diet has little to do with reflux. Your stomach produces acid in response to any type of food or liquid (even water). That being said, I do tend to avoid very spicy things (although I love mexican food), and I do not eat anything heavy in the evening prior to going to bed. In fact, I try not to eat anything for at least 3 hours before bedtime.
I sympathize with your pain, though. Acid can be incredibly painful, and even when I'm on the PPIs, and acid is greatly reduced, the reflux continues (without the acid) and is almost as uncomfortable as the acid. I know that my mother also had this problem and she eventually got to the point where she could not lay down to sleep at night. She had to sleep in a chair sitting upright.
I hope that some simply lifestyle changes can help you, and you feel better soon.