To dream of killing someone or that you are being murdered may suggest that your unconscious is trying to kill off an unpleasant or unneeded aspect of yourself. Dreams about murder may be releasing repressed rage or anger towards someone or something, possibly yourself.
To dream of murdering your mother represents feelings about hurting your future or terminating opportunities. "Killing off" your good luck or making a drastic reversal of past decisions. Killing your mother may also reflect feelings about choice or plans you regret and now you feel you have to put an end to it.