What Causes Severe Pain On Right Side Under The Rib Cage?

I am 50 years old for the last 7 years.I experience sever pain on the right side under my ribs cage, I visit all kind of doctors .i did nuclear medicine ,MRI, CT-scan, altar sound, X-Ray even colonoscopy and endoscopy & all kind s of blood work & ruin analysis.But after all this no one can tell me.What wrong with me.Why I still have this sever pain .They said it is not gal bladder,Liver problem ,you don t have Pulled muscle , once every 2 months.I visit my Dr, for the same problem for about 6 year s No result. I change my diet I still have the same pain I change the Dr, the examination and the type of medicine I got is as usual pain killer I am getting confused and frustrated please help.Thank you