@judieg-was your surgery just a septoplasty by itself or were there additional procedures with it?
What were your issues pre-surgery?
This can absolutely happen due to septoplasty. ANY alterations to the nasal cavity are going to make the airways larger. This can cause feelings of dryness, cold air due less contact with mucosal structures, which is needed for the slowing, moisturizing and humidification of air. This problem is all too common yet never discussed. These are airflow dynamic issues that cause physiological side effects of the natural nasal mucosa and nerves.
You can ask your surgeon about this.
When this was brought up to your surgeon, were you told saline rinses, gels and humidification?
The best advice I could offer is humidification for a subjective soothing feeling.