These symptoms do sound quite concerning and I agree that you need to have a thorough medical evaluation. It sounds like you should talk once again to your primary care doctor
and update them on how your symptoms are worsening. Alternatively, you could talk to a gastroenterologist
if you have one.
The fact that you are having pain and cramping with foods, especially with greasy foods, points to one of several potential problems. First, given the ultrasound
findings of something in the pancreas, I think that the most likely explanation of all of your symptoms together is that you might have some pancreatic insufficiency. Since the pancreas breaks down and digests fats, if your pancreas is not working well, you will have discomfort with greasy foods, followed by the passage of the undigested fats in your bowel movements (hence the foul smell).
Without more information and a physical examination, it is not possible to rule out a stomach ulcer or stomach inflammation (gastritis), both of which could cause pain with eating spicy or acidic foods. Also, it is possible that you have some gall bladder sludge or inflammation that was mild and not picked up on the prior abdominal ultrasound.
Get in to see your primary care doctor or gastroenterologist right away.