What Causes Constant Blockage And Irritation In Nose?

I have had a constantly blocked nose for the past 6 months. Sometimes it may be one nostril only. I get irritation that makes me sneeze, which I felt might be an allergy. I have some polyps on and off. I find it hard to sleep and I have no sense of taste. I have been given several nasal sprays and drops and an inhaler which burnt my throat, nothing relieves it for long. I feel very tired and irritable. Can you please advise what I should do now?