What Causes Stomach Pain And Frequent Diarrhea?

well, i ve been to a gastroenterologist several times, only stopping in febuary. Now however, despite medications, my symptoms are growing worse. I ve also started suffering a few new ones. I began having stomach pains in march of 08, went to the hospital, and was put on ranitidine twice daily. the pains were localized as they are now in the upper middle of my abdomen, around the stomach area, and were an acidic burning sort of pain. after a year mild stomach pains, but not unbearable, were present, until sometime mid-march of 09, when my stomach pains got drastically worse for a short time. Both times tests for any kind of kidney or stomach diseases came back negative. Sometime late january i was given an endoscopy, which showed no ulcer. My medicine was changed to a prozac in the morning and a ranitidine at night. now, however, the pains are growing worse and nearly unbearable at times. i ve also had diarrhea almost without fail for about a month now, along with the burning feeling i ve come to believe(probably incorrectly) to be stomach acid left over in soft stools. This is with exception to the past few days when i ve been trying to eat anything that may harden my stools. Now it comes out in little pebbles rather than a single stool. In addition to this i often feel bloated and full and have to force myself to eat. I also occasionally feel a bit of what i think may be acid in the back of my throat, which i usually just swallow down or force away with some food. My concern is, since i last saw my physician, i ve been incredibly fatigued, moreso than i ever was before, but have problems sleeping for more than a few hours at any given time, before lying awake for an hour, then repeating the process. Right now the pains were bad enough i got a small baggie of ice to put on my stomach. i prodded at it after the area had gone mostly numb, and found that in addition to the bloating, my stomach area, inside of the muscle, was pained, and felt swollen. I d like to stress that neither of my doctors are sure what is wrong with me as of yet. with these new symptoms, is there anything that stands out as what may be wrong? i have an appointment on thursday, but i d like to find out as much as i can before then. Also, is there anything specific i can do to alleviate the pain?