According to the Buddha, life is full of suffering. The being suffers from the very moment it enters into the world. Its suffering continues unabated as long as it is subject to the laws of continuous mutation and constant flux.
The Buddha declared that life cannot be free from suffering because it is a product of ignorance, illusion and impermanence. The events of life produce pain and suffering, because in the thick of samsara the being leaves behind him things which he holds dearly or gathers things he does not want to.
This gaining and losing, holding on and leaving behind, inability to control every event in ones own life, the inexorable law of karma that determines the turn of the next moment, fill every event in ones life with the darkness of pain and suffering. Birth is suffering. Decay, death, sorrow, lamentation, pain, grief, and despair, all lead to suffering. Contact with the unpleasant is suffering. Separation from the pleasant is suffering. In brief the Five aggregates of Existence are suffering. These five aggregates are Corporeality, Feeling, Perception, Mental Formations, and Consciousness.