Life is EVERYTHING. It includes joy AND pain, food AND starvation. It does not need a deity to function, nor do humans need a deity to ensure the world doesn't fall apart.
someone who has been brainwashed into the belief that a god created the great and wonderful and perfect and all holy Earth for great, and wonderful and perfect humans created in that "god's" own image will see pain, suffering, hurt, and sorrow (all results of nervous and hormonal functions within our neurological system) as a "problem" that needs a supernatural solution to make sense.
pain is our nerves telling us we are suffering trauma of some sort. Fear is our brain telling us that something does not feel right, based on past experience and innate knowledge. Sorrow is our brain telling us that something or someone we loved is no longer there to love. These things are shared by all animals in some form or another, and frankly, are probaly shared by plants and trees, even though they have no nervous systems.
plants can tell when the sun is moving, when fellow plants are being attacked. they follow cycles we are unaware of, and share symbiotic relationships with fungi, animals, and other plants. They do not need a religion to tell them why they suffer.