The nasal septum divides the two sides of the nose. A deviation can contribute to blockage, but swelling and other nasal conditions can also affect airflow. This is why symptoms and examination matter before choosing treatment.
When a structural septal problem is important, an ENT clinician can discuss whether septoplasty is an appropriate option and explain the relevant risks and alternatives.
References
University Hospitals Sussex NHS Foundation Trust: https://www.uhsussex.nhs.uk/resources/septoplasty-and-septorhinoplasty/