It might be hard for us to tell if a cat is in pain.
Cats are masters at hiding sickness. This is partly due to the fact that cats are both prey and predators, and in the wild, hiding pain helps protect them from predators or other cats that might be a threat. They are more vulnerable to attacks if they show signs of suffering.
Because cats hide their pain due to fear and stress, which is typical during veterinary visits, it can be difficult for your veterinarian to detect signs of pain. Your cat may also go into fight or flight mode, which can make pain perception worse.