Want can be external or internal. A character can want a treasure, or they can want to make peace with the relationship of a dead parent.
Or they can want both—and those two things can contradict each other.
In his book The Science of Storytelling, Will Storr says:
It’s not uncommon for a character to want something on the conscious level and yet subconsciously need something entirely different... Although these complex protagonists are unaware of their subconscious need, the audience senses it, perceiving in them an inner contradiction. The conscious and unconscious desires of a multidimensional protagonist contradict each other. What he believes he wants is the antithesis of what he actually but unwittingly needs.
John Truby approaches it from a slightly different angle. In his book The Anatomy of Story, he discusses need and desire.
He sees need as an internal obstacle for the character:
The need is what the hero must fulfill within himself in order to have a better life. It usually involves overcoming his weaknesses and changing, or growing, in some way.
But desire is the central want that drives the story:
Desire is what your hero wants in the story, his particular goal... Desire is the driving force in the story, the line from which everything else hangs.
Yet, need and desire are intertwined:
Desire is intimately connected to need. In most stories, when the hero accomplishes his goal, he also fulfills his need.
Personally, I try not to overcomplicate the terms. We have things we want and things that stand in our way—and they can exist both internally and externally.
Yet, complexity occurs when characters’ wants oppose each other. To show this complexity, we must build scenes that force characters to choose between these two things.
Make your characters struggle towards achieving their true want—the want you believe makes them a more fulfilled, more complete individual.
Of course, as always, it doesn’t mean they have to achieve it—but our goal as writers is to show that struggle.