Protective splinting is very common with all kinds of pain, including back pain. This is done by contracting all the muscles surrounding the painful area. This decreases movement at that site. Often the person is also holding the breath. The combination of muscle contraction and holding the breath means the body is not getting enough blood to the hurt area. This slows down the healing process.
Splinting has a good purpose in the beginning. But sometimes the body heals and the muscles are still contracting too hard and too long. This becomes a problem in recovery. Fortunately, the body "remembers" how to move normally, so it doesn't take long to restore this function. The physical therapist is the best one to help with this problem.