Re: Problems with throat, nose, & stomach.
I'm not a burper, so I don't know if I can help with that one. Maybe you have acid reflux. Try elevating the head of your bed.
If you breathe through your mouth when you're asleep, that can cause a sore throat.
As for breathing through only one nostril at a time, my guess is that you have a deviated septum. That's the thing in your nose that separates your nostrils. I'm 58 and have no memory of being able to breathe through both nostrils at the same time until a year ago when I had my septum straightened, along with some other nasal/sinus procedures.
As for the 5 second high...JUST DON'T DO IT!!! End of "problem"! My guess is that you might be cutting off some blood circulation when you do this, causing the "high" feeling.
I don't really think you have a disease. I just think you're a 15 year old young man with things going on that you don't think should be going on. If you still have concerns, see an otolaryngologist, more commonly known as an ear, nose, and throat doctor (ENT).