I have a stiff back for over a year now. I do exercises regularly which were taught to me by physiotherapy. Will my back be normal again before I die.

Re-evaluate. When you have persistent symptoms it is helpful to re-assess the root cause. First look at life style: nutrition, sleep, exercise, stress management. Avoid alcohol, tobacco, and other drugs. Magnesium deficiency can lead to muscle stiffness. Topical magnesium oil might be helpful. Check 25-oh vit d. In the summer you can readily get from sun for 20 minutes between 11 and 1 with no sunscreen.