I get terrible pain exactly where you mention when baby/uterus/body part is way up in my ribs.

It feels like you've broken a rib, doesn't it!

NOT sitting worked well for me...I walk around work every couple of hours.

Another good one is stand in a doorway and reach your arms all the way up and try to touch/hang onto the top of the door.

OR a midwife suggested one - get on all fours on the floor and rock back and forwards.

After 10-15 minutes of walking it starts to drop down for me and the pain is less.

Apart from that, all I can offer is Panadol, which I have had to turn to.