Pain is an opportunity to make energy or light. This is one reason why so many old souls have reincarnated at this juncture in history. There is so much adversity, pain, and suffering.

Pain and suffering when rubbing against the neutral or the positive creates an opportunity to make light/energy. Friction between our comfort and pain, suffering, and adversity makes energy (through the inner witness).

Energy can be stored for future work. Work on oneself - letting go attachment to pain etc. lets loose energy for personal work, work with others, and the Great Work - (of raising consciousness) for example.