Hi and welcome to Healthcaremagic. Thank you for your query. I understand your concerns and I will try to help you as much as I can. Yes, this may be irritation of vagal nerve and beside respiratory issues this may indicate specific condition called hiatal hernia should be considered and this means that stomach is protruding through diaphragm muscle. It may cause breathing difficulties,nausea, swallowing difficulties and irritation of stomach. It will also be aggravated by certain food or medications, stress and smoking. You need to avoid fried food, carbonated drinks, coffee, alcohol and spicy food. You should eat more milk products, vegetables and boiled food. Also, certain antiacid medications may be required and as last option, it is possible to perform surgical repair of hernia especially if there are progressive respiratory discomfort and dyspepsia. To diagnose it you should do gastroscopy and if this is negative as in your case then you should do contrast xrays of stomach. I hope I have answered you query. If you have any further questions you can contact us in every time. Kindly regards. Wish you a good health.