To dream of screaming represents shock or disbelief at how negative a situation in waking life is. A scary situation that has taken you by surprise. A desperate need to address a problem. Your sense of helplessness and frustration with some situation.
Alternatively, you may be powerfully expressing emotion in some manner which you has been suppressed for too long. Desperation communicating with or getting through to someone.
Dreaming of screaming may also reflect your perception of someone else's desperate need for help.
To dream that you can't scream represents mixed feelings of desperation and futility. Feeling that nothing can help you.
Example: A young man dreamed of hearing a terrifying scream. In waking life he was shocked to realize that he was losing his hair which at the time was beautiful.
To dream that you or someone is yelling represents repressed anger that needs to be expressed. If you are yelling and no one hears, then it suggests that you are being overlooked in some waking situation. You feel that your voice does not matter or that your opinion does not count. In particular, hearing demonic yelling in your dream means there is something you thought you have left in the past that is still haunting you.
To dream of yelling represents anger or frustration. You may feel overlooked or ignored. Yelling may also be a sign that you feel that your opinion doesn't count or that others see you as being unimportant.
Example: A girl dreamed of yelling a guy. In waking life she had recently made moves on a guy that totally ignored it and was frustrated that he didn't like her.