People sure do love parasites around here. Unlikely the explanation for OP.From your comment below:Entamoeba - This causes colitis, which is bloody diarrhea, not alternating stools and RUQ pain like OP describes.Liver flukes - Almost always asymptomatic. But, easy to check for with a stool O&P like you suggest.Cystic echinococcus - OP had a liver ultrasound. CE would show a bunch of cysts, and should be apparent to the radiologist.
There are some parasites that can cause liver cysts and start giving you all sorts if weird symptoms. Did you travel anywhere before symptoms began where you walked barefoot on soil/sand or drank water from a source you dont usually drink from?