See your dentist. You may want to visit your dentist to see if there is a problem causing your teeth to be sensitive. You can try using sensodyne toothpaste or other brands of toothpaste specifically for sensitive teeth.
Sensitive teeth. If your sensitive teeth are caused by gum recession you can use a sensitivity toothpaste to help. If the cause is from decay, or something else more serious you'll need to see a dental professional to help with that. Good luck!
Several approaches. There are many causes of tooth sensitivity. See your dentist to determine what the cause of the sensitivity is. Frequently, a change in toothpaste and brushing technique is all that is needed to dramatically reduce sensitivity.