Improvement with movement doesn't mean recovery
When an animal suffers from chronic pain, the first movements after rest can be particularly uncomfortable. As the dog walks, it adapts its gait and the stiffness becomes less noticeable.
Some dogs then continue their walk almost normally. Others show only mild, intermittent discomfort.
These temporary improvements sometimes lead owners to wait several months before seeing a vet. Meanwhile, the condition responsible for the pain can keep progressing, and the dog can gradually lose muscle mass.
A dog does not need to cry out or completely refuse to walk in order to be in pain.