The painbody is a semi-autonomous form of energy, made up of emotions, that lives inside most human beings. It has its own primitive intelligence, much like that of a cunning animal, and the primary goal of that intelligence is survival. Like all forms of life, it needs to feed periodically (absorb new energy) and its food is energy compatible with its own, that is, energy that vibrates at a similar frequency. Any emotionally painful energy can become food for the painbody. That's why the painbody loves negative thoughts and the drama of human relationships. The painbody is an addiction to unhappiness.
You may be surprised to learn for the first time that there is something inside you that periodically seeks out emotional negativity and unhappiness. It is necessary to be more aware to see it in ourselves than to see it in others. Once unhappiness takes hold of us, not only do we not want to end it, but we try to make others feel as unhappy as we do in order to feed on their negative emotional reactions.
In most cases, the painbody has an active phase and a latent phase. When it is latent we easily forget that we carry a black cloud or a dormant volcano within us, depending on the energy field of our particular pain body. The period that it remains dormant varies from person to person: a few weeks is most common, but it can also be a few days or a few months. In some rare cases, the painbody can remain in a state of hibernation for years until some event awakens it.
(A New Earth, Eckhart Tolle)