I have a very nasal voice. i also have allergies,i don't think it's from stuffy nose because sometimes i don't have a stuffy nose but still am nasal.

Check with doctor: I have found that many people have got used to their nasal stuffiness even when it is present. Your perception of not having stuffy nose may well be what you have got used to. See your doctor when you think you don't have any nasal problem and see what he finds. I'd bet that you do always have moderate degree of nasal stuffiness.