Pain in right side of abdomen right below where my rib cage ends. had cbc and ultrasound done over summer with no results. what's going on?

Many possibilities: Gallbladder (stones) or attack - cholecystitis, rib fracture or bruising (from sports), kidney issues, possibly problems with the liver or ovaries or the colon / intestines are all still possible. Depends on the characteristic of the pain & what seems to bring it on or alleviate it. Keep a 'pain diary' along with what you eat, & bring it to a doctor. Use HealthTap PRime if it's more convenient. GL