Single or few teeth can not suffer from a heavy brushing, if you brush too hard, more areas would show the problem (wouldn't you agree?).
Recession of the gums (or when gums pull away from the tooth, exposing yellowish root that is sensetive) more often is caused by some heavy forces on the tooth (bite problems, grinding) or the "muscle" pull of the lining of the mouth in that area (when you pull down your lip, can you see a fiber of the mouth lining pulling next to the gums around that tooth?).
Please, see your dentist and do not worry. It either can be maintained or some minor gum surgery will be needed.
Electric toothbrushes (more expensive ones) have a pressure control.