A dream with a door or a doorway symbolizes a mental or physical state shift. This could be when moving into a new phase of your life for example.
To move through a door or doorway may be a reflection of a new goal or phase in your life.
A door that is hard to open implies that you may be experiencing setbacks or constraints in your life or that extra efforts are required in some area.
A closed door may imply opportunities that are not currently within your reach, or that you feel are not within your grasp.