It is possible to have symptoms of gallbladder disease, but negative ultrasound results.
In that cases, trans abdominal or regular ultrasound needs to be switched with performing endoscopic ultrasound.
Some clinicians believe that the gall bladder pain doesn’t always occur due to gall bladder blockage with gallstones, but, due to intolerance to certain foods, like eggs, meats with high levels of fat, dairy products and citrus fruits.
Also, it is possible that the pain due to your gastritis which is usually felt under the breast bone, you feel it to the right side of your upper abdomen, too.