If the nasal septum (the wall between the nostrils) is quite distorted, the respiratory route is unilaterally narrowed and that can make breathing difficult, as air pressure sometimes can not pass through a narrow corridor. A strong deviation of the septum is not common; it is usually the result of injury, and the nose often looks completely flat. There are no significant symptoms except for a little shortness of breath, but in rare cases there is an increased tendency to sinusitis.
Septum can be easily treated with surgery, if there are some unpleasant symptoms due to deviation. However, most people simply get used to live with this condition and do not pay attention to minor symptoms that can occur.