Gasping for breath Hiatus Hernia

I am a 66 yr old female recently diagnosed with Hiatus Hernia and GERD.   During the day, I often have to yawn, or stand up to take a deep breath.   It feels as if my breath is "stuck in my diaphragm" (that's the only way I can describe it).   Can you tell me what this could be?   I do not have heart problems (had an ECG this past week) and had Lung Function Tests, which revealed normal functions.   I forgot to ask my Pulmonary Specialist about this breathing problem, so relieved was I to know that I didnt have cancer of the lungs or TB!  I will be most grateful for any help and suggestions.  By the way, I am 13 kgs overweight and have been instructed by the Specialist to lose it, which I am now working on!  Many thanks, in anticipation for your help.   "Grannyannie07"