Hi, I am Dr. Atul Kumar Nimawat MS ENT.
Your symptoms suggest a condition known as nasal cycle
A natural phenomenon where one nostril feels more open than the other, which can get exaggerated in cases like deviated nasal septum, allergic rhinitis, or nasal turbinate hypertrophy. Since you’re experiencing blockage while sleeping and in sitting posture as well, a few common causes include:
Deviated Nasal Septum (DNS)
Allergic Rhinitis
Nasal Polyps or Turbinate Hypertrophy
Chronic Rhinosinusitis
Next Steps
Steam Inhalation – 2–3 times daily helps reduce nasal congestion.
Nasal Saline Rinse (Normal Saline or Sterimar) – Clears allergens and mucus.
Health Tips
You should consult an ENT specialist for a proper nasal endoscopy and possibly a CT scan of the sinuses, if required. Persistent symptoms might need surgical correction like septoplasty or turbinate reduction, if medical management fails.