I have the same problem....driving home one day and out of the blue I couldn't take a deep breath. Went to the emergency room and was told I was probably having an asthma attack. Gave me a breathing treatment and I did feel better until driving on the way home and it returned that quick. That was 7 months ago and still happening except I've learned some breathing "tricks' to help. Also I was diagnosed with a hiatal hernia and gerd as well. However the doctors said the hiatal hernia was not big enough to affect the lungs by pushing into it, but the acid could be affecting my breathing by entering my lungs. Anyone have a diagnosis yet?