Sometimes pain can be seen as a struggle taking place in your brain. The alarm system in your brain is always making pain. It is convinced that you need to be protected! The 'thinking' part of your brain doesn't understand it: Where does this pain come from? When is this about? Especially when doctors can't find something...
Listening to your brain and body
What is the point of giving 'attention' to something as negative as pain? You can compare it to being afraid of something. Suppose you are afraid of spiders. The best way to reduce your fear of spiders is to slowly 'get used' to spiders. A psychologist who treats this will literally come to the treatment with spiders (in jars)!
One way to ensure that the alarm system can adapt is to expose yourself to your own pain. While you focus on your body, your alarm system notices that the disasters that could happen don't really happen. The 'damage' or harm your alarm system wants to warn you about is not there. After a while your alarm system will go down a bit.
The principles of giving attention to pain are especially well expressed in mindfulness. If you want to learn more about this, you can read this book!