For the past two days only one nostril has been running and congested on and off, the other nostril is fine. no other symptoms ... do i have a virus?

Nasal congestion: This can occur with a deviated nasal septum or a nasal polyp or it could be the early stages of a head cold. Irrigate that nasal passage with warm salt water and try a nasal decongestant spray for only a short time as excessive use causes rebound congestion. An otolaryngologist is better qualified to evaluate and advise you if symptoms persist.