Wow. As always, it's good to know that one is not alone in one's struggles with illness and chronic pain. Not because misery loves company - just the opposite! It's because being alone in anything is stressful and makes it hard to take appropriate action on one's own behalf, IMHO.
I come from a long line of people with major illnesses but who live a long time. Rheumatoid Arthritis, Fibromyalgia (though no one knew what it was in previous eras - they usually called it rheumatism or some other related thing), heart and lung problems, anemia, and more. My Mom, an artist her entire life (85 years), inspired me to find new ways to do things or do new things entirely whenever something I loved doing became difficult or impossible. It has seen me through to my 63rd year and will see me through the rest of my life, however long it ends up being. During my Mom's lifetime, she gave up as many art practices as she found as a result. She was in a wheelchair for many years before she died and went from doing wall-sized paintings to doing wall-sized pieces made up of 5 x 5 inch paintings put together! That's just one example of the ways she let creativity drive changes she needed to make whenever health limited her in any way.
As for me, I (like Nella) realized some time ago that I needed to do most of my drawing and painting using digital means. I used to paint and draw on paper and canvas but having fibromyalgia really made that difficult. Once I switched to computer painting and drawing, I was able to do what I'd done before but also new things which were never part of my earlier activities. ArtRage is great but I got into Painter (only available on desktop computers in the beginning) when it first came on the market decades ago (my Mom was teaching computer art at local colleges and was one of the early testers of the program, when it was only black and white and called Sketcher). Anyway, I still use that (and the drawing and painting tools in PhotoShop) for most things. On portable devices, I use ArtRage, Sketchbook Pro, Brushes, and some others I've stumbled across over the years.
Like Patrick, I also suggest some alternative ways to deal with the chronic pain directly (and/or its causes). Since my chronic pain is primarily from FM, I can only treat the causes directly through getting enough sleep and not overdoing certain things to the point of total fatigue. The hardest thing for me is not pushing through the pain to get things done. That's what I did all of my life but, now, I really do understand that it makes me sicker to do that. I have learned to pace myself in ways that most people don't have to and that's also hard. No matter how sick people have seen me, they can't stop themselves from trying to urge me on to do more than I should, all the while thinking they are helping me. Sigh.
Besides FM, I have diabetes and allergy-induced asthma. My allergies are so bad that they can't give me allergy shots so no relief there. OTOH, I am living a pretty great life in spite of all of it. The main reasons are found in the arts - besides being a visual artist, I am a singer/songwriter/composer and poet. These things have saved me from social, psychological, and physical problems throughout my life and I don't see that stopping any time soon. Maybe we should have a place to talk more about remedies and how to deal with health problems (a health topic?) but, in here, I'm thinking the main thing should be how we use art and creativity to heal and/or sustain ourselves…? Either way, this is only the beginning. :D