In about 60-70% of your post:

Briefly, explain why rates of disability have risen in the US
Then, explain why rates of chronic pain (as a disability) have risen so much and are so high. 
Explain why the illness produced by chronic pain is so hard on those who have to live with it.  Be sure to use the sociological concept of illness.  (Hint:  go back to Weitz and read about this.)  Remember to include issues of diagnosis and treatment in your discussion of the illness.    Think about what you learned about the illness by watching the documentary.
In the last 30%-40% of  your post:

Identify at least two of the most important changes that should be made in the current system so that people with chronic pain are able to get appropriate treatment for that pain.    Explain what change should be made.  Be specific.

Explain why you believe that these changes will have a big impact on the problem.