"I am also curious about the benefits of buying flower that is considered organic. Should this matter to me as a patient treating chronic pain?"
In my view, if we are using cannabis for medical purposes, as we all currently do in California, we shouldn't be using products that have harmful chemicals and pesticides in them. It seems counterintuitive and it seems as though that would increases the chances of having an adverse effect to something we are trying to use to improve our health. For that reason, among others, I would recommend searching for flowers that are organically grown.
In terms of specific flowers to help with chronic pain I would recommend a strain that has a good balance of THC and CBD. While there tends to be the perception that CBD has more medical benefits than THC, there is evidence to show that THC can have a significant effect on pain as well.