Patients with pain AND decreased movement also require more treatment when compared with patients who have neck pain but full motion. You may simply have a different kind of problem from the other patients who have already been discharged.
If you have been in treatment for a month without seeing any progress, then there is some cause for concern. But if you are making steady gains with decreased pain and increased motion or function, then you may be right on target for your particular problem.
If you have questions or concerns, it's always a good idea to bring them to your therapist. Your recovery will go faster and smoother if you have confidence in what you are doing and no doubts about your treatment.