Had rhino-septoplasty done 1month ago all stitches have not dissolved is this normal? If so how long can they take as I feel some pain and irritation

Check with your MD. It depends on the type of suture used. I imagine you are referring to stitches inside the nose. Some types dissolve in 6-8 days and others in 4-6 months. If they are irritating they can easily be removed. Just call your surgeon's office and check. They would want to hear from you if you are having any issues at all.