Is it normal to need an endoscopic ultrasound?

No, it is unusual.: Presumably, from the question, there is some disorder of the upper gastrointestinal tract. An upper GI series shows x-rays of the swallowing structures, stomach, beginning of small intestine. Upper endoscopy is passing a tube with a camera and seeing down to stomach, duodenum. If that tube can go into bile and pancreas ducts, ercp. If can also do ultrasound, it is endoscopic ultrasound (eus).