I am sorry to hear that you are in so much pain. The most comman causes of pain in right side of navel are appendicitis and kidney stones. However, usually an ultrasound detects these. If your doctor really suspects appendicitis or kidney stone then you may need a CT scan.
However, since you have a family history of Crohn’s and personal history of IBS and polyps, then further investigations should be done in this light. In all probability you symptoms are due to an inflammatory bowel condition. Blood works and ultrasound cannot diagnose these.
A number of times a gastroenterologist is able to diagnose these conditions by clinical examination and detailed medical history. At other times a few tests are conducted. Blood tests to rule out anemia, stool test to look for white blood cells, sigmoidoscopy, colonoscopy etc are used to diagnose ulcerative colitis. Braium meal and follow through, endoscopy etc are done to rule out GERD, Crohn’s disease etc. Irritable bowel syndrome is diagnosed by elimination of other causes. Gluten is a complex protein present in four main grains---wheat, rye, barley and oats. If you have gluten intolerance, then you probably have celiac disease or Non Celiac gluten sensitivity. There are blood tests called celiac test to detect gluten intolerance. Crohn’s disease is a difficult entity to diagnose. Along with gut symptoms skin disorders and arthritis too are commonly seen with Crohn’s. An upper GI series using barium dye is done to see the condition of small intestines. The degree of involvement of the large and small intestine may vary from person to person. A biopsy is the most confirmatory. An elevated ESR, low protein, minerals and iron in blood are the other findings in Crohn’s which may or may not be present. A recent advancement in Crohn’s diagnosis is video capsule endoscopy.
A comprehensive investigation is required keeping all the points in mind. Please consult your doctor regarding this.
I sincerely hope you will find this information useful in your journey towards better health.
Hope you get well soon! Good Luck and take care!