Suggest Treatment For Chronic Stomach Pain And Rashes On Body

I have a 12 yr old daughter that has chronic stomach pain every night, two month ago she got a rash (looked like bruses) on both her arms and started with shingle like sysmptoms and stomach problems started then. she has had all blood work done twice shows nothing,had cat scan shows nothing at night she is grabbing her lower stomach on both sides and then inbetween breast saying mom it hurts this is intense pain she is bowed over yelling, been to e.r. room several times diagnosed with vaculitist, possible lupus,hsp and gluten intolarce but blood work ruled all out????? please help we have changed diet tract diet no common dimoninator???? help where do I go from here