Sounds like what I have now. I had one calcium stone removed 2 years ago, passed one last year and during the past year I have had numerous occassions where my side and or stomach would fill horrible. I thought it maybe a stone but it was different than the other mainly because of the stomach area pain was there and not in previous. I had a spiral xray and it showed one up. I talked to someone at work and they described a geometry of the stone that sounds just like the staghorn type. I believe the stomach area is real good indication of the staghorn tpe. Others just give a side pain.