Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Thyroid cancer is not the first thing to think of, but it should be definitely ruled out since it may be present with such symptoms. For thyroid evaluation, you should do thyroid gland ultrasound first and then biopsy if required. Also, it may indicate a specific condition called hiatal hernia and this means that stomach is protruding through diaphragm muscle. It may cause breathing difficulties, nausea, swallowing difficulties, and irritation in the 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. To diagnose it you should do gastroscopy and if this is negative, as in your case, then you should do contrast X-rays of the stomach. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Ivan R. Rommstein