Pain is an indicator of physiological and psychological human well being. It's subjective and based on personal experience, hence mostly self-reported by the patients. The subjective pain estimation is mostly unreliable due to dependency on the subjects and their experiences. The reliable machine based methods can be devised for pain estimation. In recent times, mostly physiological methods are proposed which have their own serious shortcomings. In this work, we are presenting the contactless behavioral methods of pain estimation. Their performances indicate that these methods are not only independent of patients but also convenient for them. The pain management, disease diagnosis and treatment can improve with the adaptation of such methods.