My husband, 47 yrs old, is getting chemo and is very weak. A few days ago, he fell on the stairs and landed on his right side and right elbow. It didn't appear he fractured any bones. I started with a cold compress then later used a gentle rub of ointment with heat. Today, as I rubbed, I felt a shift or pop on his right side below the rib area. Sine then he has been in excruciating pain but refuse to go to the hospital. What was that pop and what should I do?