Last physical showed possible Fatty Liver. This whole week had pain in right abdomen/back. Ultrasound results pending. How concerned should I be?

Need other tests. You need imaging and lab tests to confirm that.....the pain not necessarily from your fatty liver....however, most fatty livers....particularly early on and depending on the type of fat and the causes.....are reversabl....go and check it out.....discuss with your doctor including diet, exercise, weight loss etc.
Metformin. The drug of choice for fatty liver is Metformin, 500 mg three times daily. Also, I recommend Berberine (herb) 500 mg three times daily; and Milk Thistle.