Well an endoscopy procedure will not show a splenic cyst. Only an ultrasound or CT scan. I have had a 10 cm splenic cyst that is calicified and under my left rib cage. Per most articles and some research, it reccomends splenic removal. However, I have seen 3 different doctors who said. Well it's been stable so wait and watch. I also have a hiatal hernia but it never had given me shoulder pain. If anything I get pain just under my sternum. Advocate for yourself. I do not think a CT of the abdomen is out of the question. They can at least look at the gallbladder, pancreases, spleen and liver. Just be persistent.