Nitroglycerin can also relieve esophageal spasm, it's not reliable for differential diagnosis of cardiac vs GI origin for chest pain. I've been through this recently myself and don't have any answers either. Nitro (sublingual) sometimes helped and sometimes didn't. Then on Friday I had a stress echo, my second in six months, again definitely negative. I'm also on Prevacid so my cardiologist doesn't think it's GI related but he also doesn't think it's cardiac.
Be careful with nitro. The last time I tried it not only did it not help, it made me nearly pass out and sent my heart rate down into the 30s for about 15 minutes. It's a strong vasodilator and can cause a serious drop in blood pressure.
Hi. If I were you, I'd try the nitro spray. I had the same thing going on for me for about a year. Chest pains centered, sometimes radiating up into my neck, mostly at rest. I never had heartburn except once when I was pregnant. All my tests came be negative also. My cardiodude didn't want to do an angiogram, though, because there are some risks, and the only risk factor I had going against me was a sedentary lifestyle. I was under enormous stress when the pains started and the fear that it was cardiac in origin added to it. I had the nitroglycerin sublingual tablets. I took them, sometimes they helped, other times they didn't. To this day I have no definitive answer as to the cause of my pains, but they seem to have subsided for the past 6-7 months. Try the nitro and see if it helps. My guess is that it won't help indigestion, but would if it was due to vasospasm or other cardiac cause. It's a less expensive way of checking what affects your symptoms.