Problems due to septoplasty - when I breathe, it sounds like the left side of my nose is whistling. What should I do?

I had a minor operation because my nose bone deviated a little bit to left after an minor accident so doctor suggested to had septoplasty . But after few months now sometimes when I breathe it sound like whistle from left side of my nose. I consulted my doctor/surgeon who had the septoplasty done. He said its normal but I feel very uncomfortable because sometimes it sounds really loud like whistling. Could you please suggest me what should I do ?