Long time use on any medication should be mandated to have periodic blood work. Unfortunately, it is not done on a routine basis for those of us on pain medication unless we are complaining of other symptoms. I recently had labs done because of my weight gain and everything was fine. (this was a cbc) But it was my weight gain the doctor order the test and it was my primary not my pm.
Sorry to hear your having issues keep in mind that gallbladder issues can raise liver enzymes as well.