Lower left abdominal and back pain. Right below ribs and above hips. The pain is sharp and gnawing. Worsens with activity. Tender to touch. Mild nausea and no appetite all the time. Blood and stool tests normal.?

Blood and stools. tests aren't enough to sort out your problem, you need good history and physical exam, possibly imaging studies too, may be a genitourinary problem, revisit your doctor or get a second opinion, it's your right, if you can't wait, go to ER, best wishes.