Hi..
Welcome to HEALTHCARE MAGIC..
I have gone through your query and can understand your concerns..
As per your complain  
nasal congestion that occurs at a same time duration daily can be most commonly due to 
allergic reaction to some unknown allergen..
Other causes of nasal congestion can be nasal polyps, sinusitis, deviated 
nasal septum etc..
I would suggest you to consult an Otolaryngologist and get evaluated and a thorough clinical evaluation and investigations like allergic testing, Nasal endoscopy etc can help in diagnosis and treatment cab be planned according to the cause..
In case of allergic reaction he can be advised to take anti allergics like Claritin or Benadryl, decongestant nasal sprays like 
Xylometazoline, steam inhalations and avoid exposure to dust..
In case of polyp in nose steroid nasal sprays, steroid injections or surgical excision can be advised..
In case of Deviated nasal septum 
septoplasty that is surgical straightening of the septum can help..
In case of sinus congestion antibiotics, anti inflammatory medicine, decongestants oral as well as nasal spray and steam inhalation can help..
Hope this information helps..
Thanks and regards.
Dr.Honey Nandwani Arora.