Right nostril still blocked almost 5 months after septorhinoplasty! Advise?

A physical exam should elucidate the problem.  If the caudal septum is deviated and obstructing the nostril opening, a cartlage graft may be needed to support it in the midline

The nasal obstruction you describe can be due to various reasons. A physical exam involving visualization of the inside of your nose would provide more information regarding the source of your nasal obstruction. 
You mentioned your septum appears to be deviated to the right side, and this can be part or all of the of the reason for your nasal obstruction. A revision septoplasty can be performed if indicated.
An exam and history would also provide information on whether your inferior turbinates are causing nasal obstruction. The inferior turbinates are structures inside your nose that can become enlarged/swollen/inflamed due to reason such as allergies. If the inferior turbinates are enlarged, they can obstruct the airflow through your nose. If this is the case, medical management (such as with nasal sprays or oral medications) or a small procedure (such as inferior turbinate reduction) may be options.
Lastly, you mentioned alternating sides of nasal congestion. The nasal cycle is normal in many people, such that partial nasal obstruction switches sides during the day. This should go unnoticed, however if you have underlying nasal obstruction to begin with, the nasal cycle can become more noticeable and bothersome.
I would highly recommend an in-office evaluation by a facial plastic surgeon with a background in ENT to further evaluate your situation and determine the best plan for you.
Best regards,Allen Foulad MD