It was very infrequent, and when I did -- a couple months ago -- have someone look into it, they had me do the barium swallow test, which showed nothing very remarkable. They told me not to eat after 8PM, in general, to sleep with my head and upper body elevated when possible, etc.
This morning I had another incident, leaving my shaky, lightheaded, and with a constant pressure feeling in my chest that did NOT abate. I couldn't finish eating, and after making a call to my doctors, was sent to the ER where I spent a large portion of the day. Obviously cardiac is another possible source of trouble, and they tried to rule that out. This hasn't happened, though they did use nitro tablets to see if it eased my symptoms. I will likely be having an endoscopy soon. I just wish I knew what the hell was causing this.