Pain When Brushing Back Teeth?

today went to brush teeth and just the upper back teeth were very sensitive on both sides. is not sensitive to hot or cold just when I brushed. Does not hurt when eating or just sitting, just when brushing and only on the top backs both sides.

Suggestion:

Proper brushing takes at least two minutes — that's right, 120 seconds! Most adults do not come close to brushing that long. To get a feel for the time involved, try using a stopwatch. To properly brush your teeth, use short, gentle strokes, paying extra attention to the gumline, hard-to-reach back teeth and areas around fillings, crowns or other restoration. Concentrate on thoroughly cleaning each section as follows:

* Clean the outer surfaces of your upper teeth, then your lower teeth
* Clean the inner surfaces of your upper teeth, then your lower teeth
* Clean the chewing surfaces
* For fresher breath, be sure to brush your tongue, too