About two weeks ago, I started to develop a stomach pain right underneath my naval that comes and goes depending on what I eat. I also have bloating and a feeling of fullness throughout my abdomen that never goes away and makes it hard to be mobile and sometimes makes hard to breath. I have more gas than usual, a different, fouler smell to my stools, and if I burp up liquid (not frequently) it is extremely acidic. I am 60 years old, I smoke and drink coffee