A scream either in waking or dream life is an expression of communication. When you see a scream in your dream, or to dream that you are the one that is screaming, you are dreaming of an expression of communication. Either you or someone else is communicating fear, anger or frustration, in a very intense way. Are you feeling these things in your waking life and feel you are unable to express them? Your dream may be suggesting that you need to find a way to get these emotions out, ignoring them is not going to make them go away.
Many people report making an attempt to scream in their dream but being unable to get a sound out. In this case something is stifling you or holding you back from communicating your true Self, and you are feeling very helpless and frustrated in this situation. In most cases you know exactly who in your life is doing this to you, and this dream is simply validating that this person is not meant for your highest Self.
The dream may point to ways where you can find your voice again, if your dream recall enables you to go this far, pay very attention to those details. If not, know the message from the dream is that the power is within you to find your voice again. The question you need to ask yourself at this point is, what do you need to do in order to do that?