Get checked for pancreatitis.
Any alcohol usage or triglyceride problems? Either can contribute.
I'm having a pain, stomach cramps and diarrhea/loose stool problem myself. But also on the right and no swelling that I've seen. The doctor thought I might have a problem with my pancreas today with pressing and ordered blood testing and x-rays.
I've had extreme pain in my stomach on eating in the past and was diagnosed with gastritis, advised to follow a clear liquid diet I think it was for 72 hours. With drastic weight loss, along with your other symptoms, you really need to get into a doctor who can refer you to a GI specialist ASAP. Sometimes even cancer can cause weight loss. There are so many things that can go wrong and I plead with you to take care of yourself and go in and get diagnostic testing!