I personally chose to address lupus, since that is my primary chronic pain issue right now, and one that I have discovered, sadly, to be woefully underrepresented in today's world, especially considering the large (and constantly growing) number of people living with autoimmune and other issues today. But I urge everyone to create their own online petition on The Petition Site -- it's totally free, and only takes a few moments of your time. You can spread the word by emailing your friends and family, posting a link on LJ, FB, Twitter, or whatever social site you're on, and take it from there!
Even if you're in a lot of pain and it's hard for you to do a lot of things, this is one thing that just about all of us can still manage. I really have no idea if online activism truly makes a difference, but I like think it does -- I find that optimism and these kinds of efforts not only make a difference in the world, but also in our own attitude and outlook, which in turn affects how we feel.
Please join the fight!