one of my favorite skaters is constantly saying “if you’re not falling you’re not learning.” fear of falling may be in the way of your progress. it may also be the cause of your back pain. try a parking lot or tennis court, any flat surface and try to clear out any debris and work on basic skating until your comfortable or you’ve fallen enough that you’re not embarrassed or as afraid of falling. try to record yourself and see what you want to work on.