I have crohns disease but I was diagnosed with that many years before my bi-polar diagnosis.
It is quite possible that your current medications may have some side effects causing your problems. Make sure to discuss your symptoms and current medications with your doctors.
It sounds like they are giving you a very thorough work out with all the blood work, x-rays, ct scans, ultrasounds, endoscopies and now the colonsocopy which is great. But make sure you tell them when you started these new meds and when your symptoms started happening. There seems to be a pattern here. You can try looking these meds up on the net and read about their side effects. Maybe constipation and heartburn are included. It's worth a try. Maybe you would just need a med change. Wouldn't that be wonderful?
When are you scheduled for your next test? Please keep us posted.