Answer this one in your head first
Then reveal it.
Someone says: 31:15 is about being told to commit shirk, which is not your situation, so it has nothing to say about your mother wanting you to move cities. What is the honest answer to that?
The honest answer is that they are right about the setting and wrong about what it establishes. The verse is not a general licence, and nobody should read it as one. What it does establish is that refusing an instruction and keeping up good companionship can exist together, since the Qur'an puts them in one sentence. Where the line falls for moving cities is a separate question, and it is a fiqh question about your case that a scholar answers and a course does not.