Have Stomach Pain For A Long Time. All Test Done And Tried With Many Medication. What To Do?

My stomach has hurt for 15 years. I have been to many doctors and have pretty much given up on doctors. I gave up dairy and feel a little better but recently I wake up with a sharp pain in my lower abdomen on my left side and my back hurts so much it wakes me up and I almost cry when I try to roll over in bed. The abdominal pain feels like it did before I had my appendix out buy on the wrong side. Once I have a BM I feel much better but it is usually with 30 minutes of struggle. My stools are not hard but strenuous, painful and I usually don't feel like I gave completed the job and often wonder if it is obstructed. I also get very bad heartburn and occasionally burp up foam that usually tastes bitter like bile.