A cat arching its back can have different meanings depending on the situation. For example, when a cat encounters a stronger animal, it will arch its back, indicating a state of high alert. If it suddenly arches its back, it's very likely that it has been frightened and is in a state of tension and anxiety; in this case, arching its back is a natural behavior.
In addition, when cats sleep for too long or maintain one position for too long, they may feel numb and their muscles may become sore. In this case, the cat will arch its back; it's simply stretching its muscles. If your cat arches its back while you're petting it, this is a sign that it's showing affection.
