Pain and pleasure are of the same nature

The Suffering of Change

Feelings of suffering change into those of happiness. Feelings of happiness change into suffering. Both arise in dependence upon internal and external causes which change. For example, we see food as pleasurable, but if we eat too much, then it causes suffering. When we are young, we see our bodies as a source of pleasure. As we become older, the same body becomes a source of suffering.

Just as a wave is always changing, so the nature of suffering is always to change. It may be experienced as pleasure or as suffering, but it arises from the same source. Pleasure arises from suffering. Seeing pleasure as happiness constitutes suffering.

...Pain and pleasure are of the same nature. Although they look different at different times, they both arise from the same sea of delusion and karmic action. Pleasure or pain, one or the other, arises and then falls back into the ocean. Thus we can conclude that pleasure and pain within the ocean of samsara are basically suffering, and dissolve into suffering.

This becomes evident in the wide variety of sudden changes of experience depicted in films. Love and hatred, happiness and family strife, peace and war, follow each other in rapid succession. The continuous change, although exaggerated in films, is characteristic of life in general.

-Ven. Gen Lobsang Gyatso