It is hard to say exactly why you are having this experience. It could be from the obstruction you describe in your nose. Some people when they have to mouth breathe feel this way. If it was in your lungs, you probably would have some difficulties during the day when you are active or it would wake you during the night. If this is of concern, I would speak with your physician. Two simple tests would help. The first is a test where you blow into a machine and it can determine if there is any obstruction (spirometry). The second is a chest x-ray to make sure there is nothing in your lungs causing these symptoms. These tests and a good physical examination would help a lot to see where the symptoms are coming from.
oh and its something i experience a lot, usually when i stay up late watching t.v or reading, i thought it might be heart ptoblems but i made an ultra sound and all that but all results were normal, and when i get this tight breaths feeling i feel like the left side of my chest is heavy, i dont cough nor sneeze nor do i have a runny nose, no allergies i am aware of, what could cause this?