My cat has unidentified abdominal pain?

My cat has abdominal pain.She was treated for swallowed object,then for parazites and then with antibiotics and nausia medicine for kidney or bladder infection.Nothing seem to work,she is in pain trying to hide.At the start she pooped and on the end blood and bile that is why I took her to the vet.That was month ago.Now,she is still in pain.She can not eat dry food she is hungry but cant,she only eats with caution wet food.She poops a little,at first she slept and walked around the toilet straining to go.Sometimes she pooped normal but small poops ,with blood and bile around at the end one time.I did not saw her urinate.The vet said the bladder is empty and she drinked water a bit.Blood work showed high leukocytes at first the after therapy was ok.But cat still in pain.Scans could not identify object swallowed.Only her intestines were swollen.But cat still in pain .She was not anemic.Could it be again UTI or kidneys stones with ok lab results for kidneys work.If she is still in pain vet says she should do contrast scan but dont know what to do anymore