Is it normal for dissolvable stiches after a septoplasty to feel very tight.

Nose surgery. Suture placed anywhere in the body after surgery will result in swelling in conjunction with whatever procedure was performed. Your bodies natural tectonics is to swell and that represents the feelings encountered after surgery in many instances. Sleep with your head up to with this as well as follow up with you surgeon.
Maybe. After this kind of surgery, there can be a good deal of swelling inside the nose. Your surgeon should have scheduled you for regular post-operative visits to check on you. If you are using the medications prescribed as directed and still feel discomfort, please contact your doctor so that s/he can ensure that there isn't anything going wrong.