I stay as active as I can and get as much (healthy) exercise as possible. I have bad joints, so high-impact exercise is off the table, but high-intensity swimming can do wonders for your body. I know what it's like to have everything hurt just because your body is damaged. I know what it's like to feel betrayed by your own physicality. The only thing that has helped me with this is to work on my body - to be the best human specimen I can be. When your body takes control from you, you need to take as much of it back as possible.
There will always be that lingering pain, and you shouldn't overexert yourself, but ceding your physical autonomy to that pain is a worse fate.