Did you know you can brush too hard? Well it's true. If your oral hygiene is good, but your gums are receding this is probably your problem.
At my last trip to the dentist, they warned me that my gums were in bad shape and I needed to take care of them more. They suggested I should get an electric toothbrush, floss like hell, and use listerine whenever possible. So I have. Now my gums are receding but healthy. But I now have damnable sensitivity to cold because of all that porous enamel that's exposed.
The only problem is that gums don't grow back. So if this trend continues (I certainly hope not) I'm going to be in real trouble.