Tanya, I've had this a few times, differing each time. The worst, and most serious, was when I had pneumonia, twice. Other times it just went away on its own.

If it's still hanging around after a couple of days, you should probably go and have it checked. I'm sure it's nothing to worry about, but better to be safe than sorry.

How do you feel otherwise? Is it getting better or worse, or staying the same?