For A Couple Of Weeks, I Have A Vibrating Sensation

For a couple of weeks, I have a vibrating sensation in the penis area. I first thought my cell phone may have started it since I have had it attached to my belt, on the vibrate status. I stopped doing this and still feel it. It is either a vibration or a sensation of filling up with liquid. No other symptoms are there. No pain in urination, no pain in sex, have been married for many years with one partner, and no urge to go to the bathroom. It happens randomly, and lasts for 3-6 seconds then goes away. It is irritating but not painful.

Any thoughts on this issue would be helpful.