There isn't a test or special sign to predict back pain during childhood. Researchers have noticed a link between children and teens with asthma, headaches, and back pain. They think these conditions may all occur in children who are more frail and less robust in their overall health. This suggests a possible genetic basis, but it remains unknown what that is just yet.
Studies do show a rise in back pain as we age. In other words, the older we get the more likely we are to have low back pain. It's also true that females of all ages are more likely to have low back pain than males. Perhaps there is a hormonal link as well.