Turn Signal problem

I own a 99 Olds Alero. The turn signals work great, they flash in the dash regular, the lights work outside, as if there is no problem with them at all while using them. When not using them sometimes a noise comes about sounding like the turn signal is clicking rapidly and it will do it for a few seconds up to 10 minutes and quit. It may not do it for a whole day but then the next day it will start to make the clicking sound rapidly. There is no lights flashing when it does this it just makes the noise. If it is making the noise when you go to use the turn signal it quits and the turn signals work great. As soon as you finish using the turn signal it goes back to the clicking sound. Basically if not using the great working turn signals it makes the noise. I even driven with the turn signals on at first because that clicking sound was driving me crazy. I went to a few places and asked and one person said a relay is getting stuck and another person said they didn't know. Can you help me out?