Perhaps there could be no joy on this planet without an equal weight of pain to balance it out on some unknown scale. ― Stephenie Meyer,
I think that pain really is the reason that we can feel joy so strongly. These polar opposites is what makes the other end more real and vibrate. While we are suffering pain, we are recalling the brighter times. This can either offer us comfort or lead us into a deeper state of despair. But part of the pain is in the knowing that it could have been different. Feeling joy is much the same way. For those that have suffered deeply, joy comes in a faltering and shy way, but when it arrives it soars higher. That height is achieved because it had to come from the depths before it could see the light. Life is fleeting and changes completely from one breath to the next. Wait and the tide will come in. Enjoy the waters while the are on your shore, because the tide will go out again.