Conflict in a story is the tension between a character and herself, a character and another character, a character and society, a character and nature, a character and the cosmos. Conflict creates situations (events) that cause the character to act and react.
It is what a character does in difficult situations that reveal who the character is, and therefore reveals the character’s humanity. The revelation of our humanity is what literature offers the reader. (Watch Tess of the D’Urbevilles on Masterpiece Classics if you want an excellent example of deep character revelation. Better: read the book by Thomas Hardy.)
The “journey” is really two journeys. the journey of the physical events of the story and the journey of a character’s soul.
It is the physical “journey” the character “goes on or through” during as she acts and reacts to the physical situations of the story. A story opens with events (the plot) and these events create the physical journey. And this is often enough in some genre stories.
But many genre writers and lit writers take their characters on an emotional/spiritual/self-revelation journey as well. The main character is established at the beginning as having a particular mindset or attitude, and who will realize the status quo no longer is possible and must reach inside to meet the challenges and either fail to do so (classic tragedy) or succeed (classic comedy) or many many points in between depending on what the writer decides to do. What changes the status quo can come from the inside of the character or from the outside, but it should set up a desire, want, need, mission, or state of mind which causes a conflict for the main character so that that character takes action until some kind of resolution is reached.
If the character has no obstacle standing in the way of her goal, need, want, challenge, then she will most likely stay on the couch with a bowl of jambalaya and watch Law and Order.
This look at basic structure is somewhat simplistic. There’s a lot more to it, but it is helpful to know that what stories do is reveal character through conflict.
This gives the writer a tool to use when rewriting so that she creates characters who will get off the couch. Unless, of course, that’s the story you are telling. Then the not-moving-off-the-couch is gonna be just perfect for creating tension between your character and her husband, her kids, her boss, her mother, her lover, the garbage man. How long can she hold out? What will she do to stay on the couch? How will she respond when they bring in the shrink, the priest, the fork-lift?
The journey is going from point a to point b.
The conflict is the car wreck on the way from point a to point b.