My doctor said i have acid reflux but i dont think my symptons support that. what do you think?

for a couple of months now i have been having stomch problems. everytime i ate i would seem to get a bad stomach ache pretty much regardless of what food it was. i would often get sick at night time while i was sleeping. it also effected my breathing to a large degree. there is no history of asthma in my family. my doctor said that he thinks it is acid reflux and gave me a sonogram to check for ulsors and it came back negative. i think it sounds more like GERD then acid reflux. the main thing i notcied though, is the biggest ociation with acid reflux and GERD is heartburn, which i very very rarely ever get. what do you guys think it might be?