Severe nasty burning god awful heartburn and bad breathing problems are my (2) main symtpoms of GERD.
Iron and Vitamin C are VERY hard on the stomach and very acid producing. I have heard there is a Vitamin C supplement that is supposed to be gentle on the stomach - do not know the name of it though. Not sure of an iron supplement that is gentle. I would check with your Dr. - also ask about a stomach medicine (like Prilosec OTC or something) - that you can take to help with the burn.
Best of luck and I hope you find relief soon.
Vanessa