Need a diagnosis

I have been feeling nausea and pain under my right rib cage which also transform into knots in my back under my right shoulder blade.  This has been going on for years and recently i have discovered a connection.  These symptoms are brought on after eating meat.  I have been dairy free for years.  Thus, I have noticed I am not a good digester of heavy protein like read meat and I feel uncomfortable for days.  Is it my gallbladder?  I did have an ultrasound done about 2 years ago that showed no abnormalities nor stones.....but my body seems to be telling me something different.  Are any other tests?

Thank you!
Miss Sunshine :)