Talk to Gastroenterologist on Breathing Issue Becoz Of Stool

Whenever stool is not passed completely, feel like a weight in lower abdomen, and feel problem in breathing. it's been an year now that I am unable to understand the reason behind this breathing issue and this issue has caused me anxiety problem and I have started fearing situations where I am alone and there would be no one to handle me. I want to know the root cause which I think is this, that when the stool isn't passed completely it causes GAS or something and I have taken this issue to my nerves.