Good question. Many studies over the last few years have shown that back pain is more about stress, anxiety, and other psychosocial factors than it is about a specific back problem.
The first week or two after a back injury is focused on reducing pain and inflammation. It's been shown that after 14 days the acute back pain patient becomes more subacute. The next step is in a downward decline is to become a chronic back pain patient.
The therapist must focus on movement and function to prevent chronic pain and long-term disability. It sounds like your therapist is up to date on the latest research findings. Give it your best effort and see if you don't get better.