15 yr old Son still sick after gallbladder removal 2 yrs ago

Son had HIDA test and only had 15% function of his gallbladder so, surgeon removed it 2 yrs ago.  He was so sick before it being removed and now, almost everyday he complains of his stomach and back hurting.  They did an MRI on abdominal area a few months ago and didn't find anything.  He does have back problems also.  His liver enzymes also came back 3 times higher than what a normal adults should be so they did scan on it also and dr says fatty liver.  I'm just worried of why he is always sick and in pain and he's missed so much school over this.  I'm at the dr's office every week with him and I think the dr is really getting tired of seeing him and thinks it's in his head.  Also every time dr presses on the area where his liver is, it raises him up off the table...in severe pain.