Could exercising (walking 2 miles @ 3.5mph) 4x a week make my crps worse? i can anywhere from mild to moderate pain depending on the day.

While it may cause: Temporary increase in pain during the walk, it is beneficial over the long run as you will avoid progression of the dystrophic aspects of crps and also avoid functional decrease by way of atrophy and contractures of involved musculature, as well as slow progression of osteopenia of involved bones. There is also evidence that moderate activity can decrease pain through endorphin release!