Ok you are trying to do a maze just using what's on screen, and I'm doing a maze based on what's in memory.
Essentially you draw a maze based on what's in memory. Your approach is not going to work correctly.
A player cannot touch a wall in the maze because you do not allow him to move if there is a wall. He will never hit a wall. Now if you want to track the maze coordinates in memory and do a collision test, that opens up a whole new plethora of issues.