I had 16% ejection fraction; they removed my gallbladder about 2 months ago. No stones, but signs of chronic inflammation.
Pain is now worse and is daily; spikes after I eat (virtually no matter what I eat). Gastric scope showed no ulcer disease. The pain is typical for pancreatitis, but blood enzymes are normal. This has stumped the doctors so far.
Basically, I have no idea what causes the pain to continue, but I have read that up to about 30% of people who have their gallbladder removed with no stones in the gallbladder have what they call "post-cholecystectomy syndrome," which may be caused by numerous things. Takes a while to get it sorted, but one study showed 95% are eventually shown to have a functional cause.
Good luck to you!