Back pain is common for many people. Unfortunately though, there can be many causes for back pain and there isn't a way for us to tell you how to help it or work around it because you would need an in-person assessment. It could have been caused by the excessive jumping rope since that is a high impact exercise and can be hard on your joints and body in general. The best thing to do is to talk with your doctor about this to make sure there isn't something more going on with your back, as you do not want to cause further injury or problems. In the meantime, generally resting and icing it may help temporarily and of course staying away from high impact exercises.