I don't know the source of the .2 recommendation, but Dr. Philip Lee Miller of LEF (his book is entitled "Life Extension Revolution") gives a target of less than 0.5 mg/L, and I've found his targets to be rather strict.
I suppose that inflammation from any source, including back pain, could raise one's levels. I know arthritis does. Dr. Miller gives a list of supplements that can help to lower CRP including nettle leaf extract, fish oil caps for adequate EPA/DHA, bromelain, ginger, curcumin, DHEA, Vitamin K and ginkgo biloba extract. His dietary recommendations include salmon & other fatty fish, avocado, olive oil, nuts & seeds, vegetables & fruits. He cautions against too many egg yolks, organ meats & fatty cuts of red meat (but I think this might not apply to grass fed?) because they are very rich sources of arachidonic acid, a precursor to pro-inflamatory cytokines. Also he said to avoid white bread & pasta, fruit juices, potatoes and white rice if you want to lower CRP, but I expect you may already be doing that.
Starting Weight: 197.5
Current Weight: 123
Lost 75# eating low carb (20-40 g) and then MDA primal low carb. Tried many other options but only LC helped me lose weight and improve health. Now at a good weight, I find my body can tolerate a few more carbs but rarely go over 100 g.