Hi I have a real bad pain under my right rib cage, it happens mainly at night which makes sleeping pretty much impossible, it feels like someone is squeezing my insides causing so.much pain I feel like throwing up, I have had tests for gall stones but it hasnt shown any traces, the pain lasts around 3 to 4 days and happens about once a month. Also the pain travels round my back, do you have any idea to what this might be?