Yes. Sensodyne tooth paste can really work to decrease sensitivity. You need to use it in place of your regular toothpaste for a few weeks to see results.
Of course. It does a good job of reducing sensitivity due to the effect of the potassium nitrate. Ask your dentist for more information.
Yes! It can work, but more important is to make sure you are not causing the sensitivity by brushing too hard causing 'wearing away' of the gums (most common cause of sensitive teeth).
Try Enamelon. A newer alternative is Enamelon which is only dispensed by dentists.