The EXISTENCE of suffering is a problem for theists because it contradicts their worldview.
The EXISTENCE of suffering is not a problem for atheists because it is compatible with randomness of the universe.
That is not to say, however, that suffering cannot or should not be ameliorated. But, it is not intrinsically evil. Evil is a word with religious overtones. Suffering just is. And as humans who are empathetic to others' negative feeling states, we try to be as prosocial as possible and help others. We do this because humans are a strongly social species.
Something doesn't have to be intrinsically evil for us to want to do something about it. Sickness isn't evil, yet we want to cure it. Having a dirty house isn't evil, but we want to clean it. Getting bad grades isn't evil, but we want to improve them.