A castle in your dream or vision tells of reward and recognition for what you have accomplished. Another explanation is the desire for comfort, wealth, generosity of other people that may not be experienced realistically.
Yet another explanation is wanting to be surrounded by strength and powerful people, but also seeing challenges that are not for everyone. An alternative explanation is that dreams or visions about a castle tell you to believe in fairy tales and in dreams.
An alternative explanation is that a castle reflects the feeling of being enclosed, private territory, your heart, your base, your resource - that which you don't want everyone to see and/or know. Another explanation is that you may overcome the limited thought, building walls, locking in old unhealthy patterns - not being able to open your true self no matter what the reasons or motive.
Yet another explanation is that a castle reflect old patterns that have been present for generations, karma, past lives and may now surface and/or be processed. In addition, there is a spiritual alternative explanation that indicates the feminine energy, feminine wisdom, nurturing qualities that are necessary to get where you want and/or need to be.
Dreams or visions about a castle lord, castle woman, castle owner are telling you something the way you present yourself to the world, what you would like to be and/or what you would like what other people see. Your character traits are reflected in this, you possess the ability to see or recognize challenges, opportunities that are not for everyone, you have found the traits and opportunities to be successful.
Another explanation is the desire for comfort, wealth, generosity of other people that may not be experienced realistically. Yet another explanation is wanting to be surrounded/attracting powerful and powerful people.