Upper left abdominal pain with bile vomiting

I have periodic (sometimes 5x year) where I have to go to the Emergency room for severe left upper (just below the rib cage) feels like someone is twisting and pinching from inside.  On a scale of 1-10 it is a definate 10...along with this is vomiting greenish bile about twice a hr.  Once at the ER they give me Morphine, zophran, and IV fluids and I am fine by the afternoon.  I have had CT scans, xrays, ultrasounds, blood test, scopes, drank white solution and watched my insides light up on the monitor....still everything is normal they say!  
Meds I take daily: xopenex inhaler for asthma, and dexilant 60 mg.
On my last visit to the ER the Dr. gave me Vicodin and promethazine for the pain and vomiting....but these never help when the symptoms come on....I always have to go to the ER.  What could be my problem??