Clinical Research Project Struggle

I am struggling to narrow down my CRP topic. It shouldn't be so difficult. I have known for a while that I wanted to do a paper on chronic pain and depression. So, I could write volumes of information on that alone. Thus, the need to narrow it down. I have decided that I would focus on Complex Regional Pain Syndrome (formerly called Reflex Sympathetic Dystrophy). Now, to figure out what I want to focus on with that syndrome. How do I make an original contribution? That is what I am struggling with. So, with the help of my chair, I have come up with a couple of ideas:

1. develop an intervention to prevent depression from occurring as one enters a pain management program: early vs. late intervention
2. psychological aspects that contribute to depression and pain, develop a tool to assess those that are likely to get depression versus those that don't when they have chronic pain.

Ah, the decisions that have to be made. Maybe I need some divine intervention. Pray for me?! I think once I have my topic, the writing won't be too difficult. Just tons of reading and compiling of information. At least I have about a year and a half to complete the monstrous task.