In most theoretical physics such as quantum field theory, the energy that a particle has as a result of changes that it itself causes in its environment defines self-energy \Sigma, and represents the contribution to the particle's energy, or effective mass, due to interactions between the particle and its environment.

What is the difference between self energy and potential energy?

In electrostatics, self energy of a particular charge distribution is the energy of required to assemble the charges from infinity to that particular configuration, without accelerating the charges. It is simply called the electrostatic potential energy stored in the system of charges.

How do I get self energy?