If your back pain isn't too severe then just waiting and seeing your regular doctor about the back pain is what's best since usually the urgent care won't be able to do much except maybe give you some pain medicine for the back pain.
If the back pain gets too severe though then the urgent care visit would be a good idea so they can see what's causing the severe back pain.
Trying taking some over the counter pain medicine and use a heating pad to help relieve the back pain and if it gets worse then go see urgent care.