I will offer this advice as well. I don't know if you still have your gallbladder, but when I was having gallstone attacks a few years ago (before having my gallbladder removed) they would begin with a tightness around my chest throughout my ribcage. It would start out at the bottom - almost like I had TOO MUCH air or something - at first I would think it was gas pain then the pain and tightness would spread up my chest.
It was so uncomfortable I would be gasping to breathe within about 15 -20 minutes. It could get pretty painful and I would at times start to sweat and heave badly cause the tightness made breathing so hard. They were misdiagnosed as anxiety attacks, so I continued having them for several years and they got progressively worse. By the time we started looking into them further (I had abnormal blood results that prompted further study) I was having all of the above symptoms along with vomiting, feet tingling/itching (which actually IS a symptom of gallbladder disease/gallstone attacks and my attacks had stopped happening ONLY during waking hours and were waking me up at all hours of the night and had gone from lasting 30 minutes or so to lasting 2 hours or more.
For me gas pain is a "fullness" where I feel full of air. My stomach gets this pooched look to it and my whole torso just feels tight - THAT is what I had with the gallstones. I am not sure if your gas pain is different than that. I just wanted to clarify in the event that your gas pain was lower in your midsection (sorry if that was confusing).
If you still have your gallbladder I would maybe ask if there is a possibility of that being the problem. They kept telling me that because I had NO back pain that is apparently typical with gallstones and NO stomach tenderness when they applied pressure (unless I was having an attack) that I did NOT have gallstones, turned out they were wrong.
I wanted to throw that out there since you said that it woke you up last night.
Also to add - I couldn't associate my attacks or issues with a food item BUT was able to associate them with drinking carbonated beverages. ANY time and I do mean ANY time I had a carbonated beverage of ANY kind I would begin having an attack within about 1 hour at the latest within 3-4 hours. I was experimenting with foods and such to pinpoint the culprit and that was the ONLY thing that I could pin down to always being involved when I was having issues. I cut sodas and all other carbonated beverages out of my diet for several months until I could be schedule for surgery and had only 1 attack ... when I slipped and had a soda with pizza. <img src="i/expressions/face-icon-small-smile.gif" border="0">
Take Care and hope you find out the problem soon,
Lindsey