To dream that you are being tortured denotes that you feel helpless in certain aspects of your waking life. Alternatively, it is probable that you are showing signs of sadomasochistic tendencies.
To dream that you are torturing others or see others being tortured suggests that you are castigating yourself for your own failures and wrongdoings. You are mirroring the person or animal being tortured.
Alternatively, the dream may indicate bottled-up emotions of vengeance.