To dream that you are crying signifies a release of negative emotions that is more likely caused by some waking situation rather than the events of the dream itself. Your dream is a way to regain some emotional balance and to safely let out your fears and frustrations. In your daily lives, you tend to ignore, deny, or repress your feelings. But in your dream state, your defense mechanisms are no longer on guard and thus allow for the release of those feelings that you have repressed during the day.
To see someone else crying in your dream, may be a projection of your own feelings onto someone else. If you do not cry in your waking life, then seeing someone else cry may be a little easier to deal with then seeing yourself cry.
To wake up crying represents some suppressed hurt or previous trauma that is coming up to the surface. You can no longer suppress these emotions. They need to be dealt with head on.
To dream that no one hears or responds to your cries represents your helplessness, difficulties and frustrations in trying to communicate with others. You feel that your words are falling on deaf ears. Perhaps your dream is telling you to be more vocal and work harder to get your point across.