Talk to Gastroenterologist on Stomach And Digestion

I had a severe constipation since many years. It was increasing my weight and it creating problems for me. Then I decided to treat it. I went to a reputable hospital and get many test done on doctor's request. I was on a medication and it was all fine.. but then suddenly I'm facing problems like diarrhea as soon as I eat something, stomach pain as soon as i eat anything, and after it I feel like eating something because my stomach is empty. Then I visited a nearby hospital and Dr prescribed me a medicine. I was well for 2 days and then his medication treated my diarrhea but I get trapped gas problem. Which is sooo painful. I can feel stabbing pain in my left side of the chest all the way to my left arm. Suddenly the pain vanishes and then it comes back. I can't even sleep. Please help me find relieve. I have acid reflux problem. Due to limitation I have attached few files. I can provide more details if required. Prescription in blue is the latest. Please help me.