There are definitely different levels of intensity of heartburn. I don't always get the stomach pain or the belching either but I do get the reflux. Maybe you don't notice the reflux because it happens while you are sleeping. This is common and especially if you eat soon before going to bed. I have woken up many times with an inflammed throat because of the nighttime reflux. I have gotten sores right above my tonsils from reflux so I can relate to the "canker" sores. Bad breath also is a common symtpom of GERD. I gargle with mouthwash and it seems to help get the not so easy areas that the acid reflux gets. I hope the doctor has answers for you but it does sound like GERD to me.
IBS, Diverticulosis, GERD, Disc Degeneration
"If you don't like something change it; if you can't change it, change the way you think about it" - Mary Engelbreit