What Causes Recurrent Pain Around Rib Cage At Night?

i have reoccurring pain in my right side which starts under the rib cage and radiates around to the front. It has a burning sensation. It occurs at night after 2-3 hrs. of sleep. Eventually I have to get up and the pain usually subsides somewhat after the pressure is off. Could this be a pinched nerve? What is so ironic is the fact I have a burning sensation down the left leg where the sciatic nerve is. My side does not hurt during the day, but I can tell something has been going on as there is mild soreness to the area. Help, please.