Re: liver pain?
The liver itself has no pain sensitive nerve endings in it, but all the surrounding tissues and structures do...
Many feel the pain people feel with inflamed livers is due to swelling of the liver stretching the surrounding tissues. If this is true, I would assume pressure from the outside (pressing on your liver) would further stretch surrounding tissue and cause an increase in pain.
Many doctors describe "pain on palpitation" (of liver) when doing examinations for liver diseases and conditions. "Rebound tenderness" where pressure does not cause sharp increase in pain but pain increases after pressure is let off is also described in some abdominal examinations though I haven't seen rebound pain associated with liver issues.