Foul smelling, muddy and semi-solid, semi formed stools for the past 7-8 months. ultrasound abdomen perfectly fine, but no respite despite taking meds?

Time for colonoscopy: If stool cultures, parasite exam, and us are normal, and a consult cannot come up with another reason for the change, you need a colonoscopy to rule out inflammation of the colon lining.

Need more testing.: An ultrasound will not tell us if something is going on with your intestinal tract, which your symptoms would suggest. If your symptoms have not relented despite medications, then a new investigation would be wise - blood testing, CT of the abdomen, EGD, colonoscopy, capsule endoscopy, stool studies.