People who have chronic pain often develop pain behaviors. The idea is that people communicate their pain by changes in the way they act. They may start to rub the painful part or walk with a limp.
Facial grimacing, moaning, and other actual reports and complaints of pain all fall into this category of pain behavior. Guarding such as bracing the body and muscle tension is a key feature of pain behaviors. Studies show that higher levels of guarding are linked with more days lost at work and less chance of getting back to work.
There have been many explanations for pain behaviors. Some experts think this is a way of coping. It could be that people develop pain behaviors as a way to avoid pain. This is called avoidance behavior.
Your neighbor's doctor may have just been describing his or her observation of your neighbor. The significance of pain behaviors isn't entirely clear. There is some evidence that certain behaviors (such as guarding) predict the development of chronic pain.