Can you advise on neck posture problem and is surgery needed?

For as long as I can remember I've had what I thought was a cervical problem, I had my chin tucked inwards whitout even realizing as my default posture, similar to pic related. This caused a poor jawline that "melts" into the chin. Because of this, some time ago I had a neck lipo hoping to solve the problem but with no results. My question is what could cause this type of posture: Is it weakness of a muscle group in the neck or a jaw angle too steep? And what could I do to solve the problem?