The right shoulder pain associated with hep C should not hurt with a change in position. It sounds more like muscle pain to me. When the liver causes pain in the shoulder it is because the liver is inflammed and is pressing on the capsule it sits in, which shares a nerve with the diaphragm. That nerve is what causes the pain. Hope you feel better soon.
I had a fair amount of neck pain when I was on treatment. Hard to say if your pain is liver related but it could be treatment related. Probably best to run it by your doc if it doesn't let up in a day or so.