I've got very similar symtoms as yours, and mine started about 5 years ago as well. I didn't have septoplasty, but I had middle turbinectomy. Didn't help! wasted $4000!
My nose clears more or less during the day, but at night times and when I sleep, I always have one side blocked, but sometimes both sides gets stuffed up.
Tried everything as well, like steroid or saline sprays, rinse, diet change, you name it, didn't help.
What I figured out after reading and researching rhinistis for years, that temperature and humidity influence tcan cause congestion.
When I had my surgery back n 2012 my nose was fully blocked, no air passed through, none. I lived in a city which was very hot and humid, tropical climate. After the surgery I though that it will clear up after a few weeks, maybe a month, but didn't. So I decided I experiment, and travelled to far away places and stayed there for a few weeks. And guess what! What a change it was! My nose got cleared up, not fully, but was able to function normally. I hated that idiot ENT who tried to convince me that this congestion is due to my allergy to dust mites. Really?! no dust mites in Sydney, or Melbourne, Europe or Asia?!
So after being pretty sure that humidity is one of the major factors, we moved.
I have been living in a much dryer climate for a year now, and though my nose never got fully congested, I'm still experiencing stuffed nose every night, and sometimes during the day.
I've seen recently an ENT in a public hospital, who after looking into my nose with that little camera concluded that I have enlarged inferior turbinates and I could benefity from a turbinectomy. Another surgery. But said, can't guaranty it will work! well that was very helpful! A 15 min consultation, I wasn't really convinced, so I am going to see another specialist soon. I'm not holding my breat, probably will advice the same.
I'm terrified having another surgery because what I was reading about ENS.
Have you also had turbinectomy or just septoplasty?
My cousin also had septoplasty not long ago, didn't work for him either.
What are you allergic to?
Also what you should know, that the tests are just for the very common things, but you could be allergic to something which is not included in the test.
I don't think allergy is the main cause of your problem, because you don;t have allergy reaction all the time and your nose also stuffs up regardless of being exposed to those allergens or not. But if you are exposed to those allergens, it certainly won;t help and makes it even worse.
I tried immuntherapy for a few month, didn't work obviously, cause it was for dust mites. There is no such thing as immuntherapy for humidity.
Have you seen any other specialists?