Chronic abdominal pain, frequent/urgent bowel movement. Diahrea, colonoscopy, gastroscopy, fecal occult blood, all normal result. Is IBS likely?

IBS. Normal colonic/ileal biopsies rules out inflammatory bowel disease, as these shows some certain histological features. Also, normal duodenal biopsies from the bulb and second part, rules out celiac disease. IBS can be diarrhea or constipation predominant. If your abdominal pain is somewhat relieved after defection, this suggests IBS.
Possibly. The symptoms described are found with inflammatory bowel disease but one should also culture the stool to make sure there is no chronic c.difficile infection or e.coli infection that may need superimposition of a normal bowel flora to the bowel. Occassionally a SB camera pellet can display video of the bowel to indicate if IBS present.