One thing you might want to look into is a HIDA scan to check your gallbladder's ejection fraction. This is different from an ultrasound in that it doesn't image the gallbladder, but checks to see how much bile your gallbladder is producing. If you're producing too little, symptoms like nausea, upper right quadrant pain, etc. can result. Many people with a low ejection fraction get their gallbladders removed and feel quite a bit better.
Also (this is less likely) you might want to re-check is your thyroid-stimulating hormone (TSH) level. It's a simple blood test but docs don't always perform it regularly. Sometimes an overactive thyroid can lead to increased frequency of bowel movements (it's actually one of the hallmark signs). Or you can look back at the results of your bloodwork and see if they ever did one.
I have heard about pain-predominant IBS. Although most people do have bowel changes, it's hard to exclude someone from the IBS realm simply in the absence of them (especially since we don't exactly know what IBS is).