To dream of a castle means good fortune is coming to you.
A castle can represent the fantastic, the unattainable or perhaps difficulty in obtaining our objectives.
See buildings, castle and tower
(See Castle; Citadel; Fortress)
(Castle; Citadel; Stronghold) A fortress in a dream means obliterating something from its roots or eliminating one’s trouble. A fortress in a dream also represents a positive power that eliminates negative forces, or it could represent good verses evil. Entering a fortress in a dream also could mean growing in piety or developing ascetic detachment. […]
The castle or fortress has been seen as a defended space since medieval times and, therefore, can be taken to represent the protected feminine. Its connection with the great mother and her attribute of wisdom arises from this concept.
A type of figurative protection, i.E. A moat around a castle; see “bush”
Dreaming of a castle links us to the principle of an enclosed and defended private space. Spiritually it suggests some kind of test or challenge or overcoming obstacles in order to gain greater understanding.
You might also like to consult the entries for camelot, castle, hero / heroine and quest as well as the information on hero in archetypes in the introduction.