Headphone jack malfunction

The headphone jack is a physical piece of hardware. Something inside could have bent or broken. Something could have become lodged in it. In either event there is no solution except to take it in for examination and repair. You might take a look with a strong light to see if you see anything. You might put a small amount of dielectric grease (found in any hardware store electrical section) on the tip of your headphone plug and GENTLY push to see if it goes in.

Well then, as I said, there’s nothing you can do about it except take it to an Apple Store or authorized Apple service provider for examination and repair. Unless accidental damage is discovered the repair should be covered under warranty. That’s it.

Excellent!