From the history given by you we could think the leg pain you are mentioning could be part of an
autoimmune hepatitis. The
Infectious Mononucleosis can also cause these symptoms you mentioned. The
elevated liver enzymes and splenic enlargement point towards autoimmune hepatitis. To confirm the tests such as Serum antismoothmuscle Antibody,
Anti Nuclear Antibody and serum protein electrophoresis and quantitative
Immunoglobulins. It is not common for an Infectious mononucleosis infection occur along with autoimmune hepatitis. Regarding the Gall stones they should be untouched unless they cause clinical symptoms and signs like Jaundice and Pain. Check if there is increase in direct bilirubin due to Obstruction.