Why is my one side of my nostrils bigger than the other? (Photo)

Thank you for your Question.
The operation will be done by using the latest Ultrasonic Rhinoplasty device Piezo®:
In traditional Rhinoplasty, surgical instruments known as rasps and osteotomies (hammer and chisel) are used to reshape the nasal bones by removing the hump and/or narrowing the nasal bone width. These tools are relatively imprecise and their use can lead to contour irregularities, etc. if not used in the proper manner. Recently, a technology that uses sound waves has been developed to contour nasal bones in a precise and far less traumatic way when compared to traditional techniques. Ultrasonic, or Piezo, Rhinoplasty is now the most advanced technology available for minimally traumatic nasal bone reshaping and hump removal during Rhinoplasty. There will be hardly any bruising and swelling which will make the recovery period a lot easier for the patient.

From the Very limited photographs, you appeared to have a caudal septal deviation, which Maybe blocking airflow on the left side of your nose.