Hi, and thanks for your medical question on eHealth forum!
Nostrils can be blocked due to a number of causes and may not be only due to secretions. Nasal polyps, inflamed nasal turbinates, hay fever, allergic rhinitis, and sinusitis could be the cause.
Decongestant nasal drops may help and so might saline water but it should not be tried without a confirmed diagnosis. Please consult an ENT specialist. Hope this helps. Take care!