I've never heard that the liver has no pain receptors, so I did a little online searching. (And asked my fiance, my personal expert. )
Any disease, disorder or condition that causes inflammation in the liver can cause pain. That can be something as simple as mononucleosis or, as you know, as serious as cancer.
The problem is that most pain meds are processed through the liver and are, therefore, contraindicated in a patient with liver disease. That's why it's so difficult to manage.
God Bless. Let us know how you both are doing and if there is any help we can provide.