Persistent upper right abdominal pain not brought on by eating or other activities for 3+ months. also radiates around back. normal u/s. what next?

12th rib: The 12th rib is a short nub of a rib that is not attached to the other ribs. It can become inflamed and hurt the way you describe. No test will show it. If someone standing behind you can find that rib and reproduce your pain by pressing on it then that may be it. This problem is often overlooked. It is often caused by leaning against the arm of a chair wile on the phone.