I Keep Feeling My Pulse Pounding On On The Left

I keep feeling my pulse pounding on on the left side of my head. This started a couple of weeks ago when I had a congestion, fever and bronchitis. The symptoms have abated, but the pulsing on the one side of my head still continues. There is no pain associated with it, only the constant pulsating in the area of my left inner ear. What could cause this?