I'm having a hard time determining the relationship/differences between interaction energy and forces. Say we have a system of two charged particles. Each particle will exert a force on each other (from Coulomb's Law), but also defined is an interaction energy between the two particles given by Coulomb's Law multiplied by the distance between them (reducing the $r^2$ term in Coulomb's Law to just $r$).
How are these concepts related? What is the correct way to interpret the interaction energy?