Based on the ultrasound results, it seems that you have gallstones in your gallbladder, which  is causing abdominal and back pain, nausea, and headache. And  endoscopy is not required to diagnose or treat gallstones. But in some cases, an endoscopic ultrasound is used to get a better view of the gallbladder and surrounding structures. I recommend consulting with a gastroenterologist or a surgeon for further evaluation and treatment options.