If you have a physio they will tell you to keep moving. This is for a reason!
If we don’t regularly move joints through a full range of movement during the day our joints, muscles, ligaments and tendons WILL tighten leading to pain and discomfort. (A painful lower back or sore shoulder is no fun on top of everything else).
If you don’t have a physio but are getting stiff and sore from being inactive then ask to be referred for advice on stretches and exercises to help.
Whenever possible, a little bit of movement, even if it is stretching regularly, will save you from pain and discomfort. It’s really hard to motivate yourself to keep moving when you’re tired from your illness, after surgery or because your medication is making you feel rough but do your best to keep the rest of your body moving. When sitting watching TV etc. set a kitchen timer as a reminder to get up and stretch every half hour.
If you have a physical problem e.g. a painful lower back, that is not a part of your condition and not responding to stretching and/or painkillers, don’t be afraid to ask to be referred to a physiotherapist who specialises in treating musculo-skeletal problems.