I have the same problem. It started about a year ago and soon I started spitting up phlegm after eating along with the shoulder pain. The pain and phlegm continually increased and eventually I was spitting up the food that I had eaten. It was not digested at all. I realized that when the food came up, the shoulder pain stopped. It took a year for it to slowly progress to this point. It turns out that I have gastroparesis. My stomach doesn’t empty fast enough. I’ve learned to eat very small meals and to not eat unless I am truly hungry. I have to take small bites and chew my food very well. I also take vitamin and mineral supplements. As long as I don’t eat too much at a time, it stays down and I have no shoulder pain. It’s as though I had stomach stapling surgery that some people have for weight loss. Fried or fatty foods affect me the worst and I’m supposed to really watch my fiber intake. Too much fiber can build up in my stomach into azores, (I think this is the right word and spelled right) which is like a rock. I’ve heard that it’s something that no one would want to go through. I also have Crohn’s disease, but I believe that it’s coincidental. Of all the symptoms, the shoulder pain is the worst for me. I tried heat and cold but nothing helps. It hurts so bad that I can’t stay still so I just walk around. And I couldn’t understand what my shoulder had to do with my stomach problem. My doctor and I finally decided that it is referred pain. My stomach being too full affects a nerve that leads to my left shoulder. I like knowing why something is happening so learning this helped me. They say that everything has a bright side and mine is that I’ve lost thirty pounds. I could stand to lose twenty more to get to my ideal weight, but I’m a little bit worried about what I will do to keep from losing too much. I’ll just face that problem when and if I get to it. I hope this helps you. Good luck!