Just goes to show you can do a bit of walking and get outside (as you do for your appointments). Even if it's only for a 3 or 4 minutes. You could walk downstairs and sit outside for two minutes and do that twice a day. Then you could build it up each week adding more time. Guarantee it would help you big time and it would get easier. Easier on the pain, fitness and easier on the social anxiety of being outside.