Arm pain

On Thursday I fell while at work from a step stool and landed on my left side/arm. I’m about 5 feet tall and the step stool was 18″ high. At the time, I had no pain, and the only sign of injury was a scratch 3 inches long that barely broke the skin and a tiny bruise, both on my inner forearm. Yesterday, a bit over 24 hours after I fell, my arm began to ache. The pain is worst around my elbow. It has continued to ache today. There’s no discoloration or bruising, and the arm doesn’t looked deformed in any way. I can move the arm fine, it just aches moderately. The most painful spot is just above my elbow. Sometimes my fingers feel a bit numb. I’ve been taken Ibuprofen for the pain, but don’t know if I should be doing anything else. Is it normal for pain not to appear for 24-30 hours.