Had Septorhinoplasty Done and Cant Breathe Through a Nostril After 11 Days Post Op??!

Having complete blockage can be from swelling, but you should really have your surgeon check it out to make sure nothing else is going on. Often people note some rebound congestion once the splints are removed. It's too early to assess if any other surgery needs to be done.
 

In some patients some of the swelling will recur after the splints are removed. I would tell one of my patients in a similar situation to return in one week to be reevaluated. However most of my patients breath quite well immediately after the splints are removed. Furthermore there are other structures such as tr turbinates and internal nasal valve that at times needs to be addresses to improve breathing.

The ability to breath well through the nose after rhinoplasty varries greatly from patient to patient. Ask your surgeon to examine your nasal passages and i am sure he can explain the issue based on what he did and how you are healing