Only at night i get this lump just below my right side rib cage. i can only feel it when i am standing, when i lay down it goes away. could it be just trapped gas? or something more? it hurts sometimes but subsides normally once i change positions?

What you are describing sounds very much like a Spigelian hernia (weak area in the muscle thru which bowel protrudes )which is relatively unusual but it is difficult to diagnose without exam. It is not serious Once diagnosed it is easily repaired. See an experienced surgeon and give exactly the same history. Let us know how it turns out. Good luck.