Well, for those who believe in spiritualism, dream and the likes, someone holding you down in a dream basically means someone is trying to stop you from achieving a notable feat or someone is trying to stall your progress in life. It could be the person you see in the dream trying to delay your progress in reality or someone else but the bottomline is that such a dream means you as a person is being pulled down, stalled, delayed or stopped from progressing or achieving certain feats you're set to achieve in life. Those who believe in spiritualism believe dreams are powerful tools of communication, a way the forces and spirits communicates to us to warn us of impending danger or bring good news to us. Even the two ecclesiastical religions believe in the power and potency of dreams. Hence they'd give same interpretation to this
However the free thinkers and radical scientists often argue and believe that dreams are just extentions of our thoughts before we go to bed. They believe that since dreams occurs during sleep when the mind is in a lucid state, the mind only focuses on the last thought before we sleep and projects it as a dream.
Notwithstanding, a dream of this kind is negative and a powerful warning to the dreamer to be weary and careful as there are people and forces trying to delay him or stop him from doing certain things.