There are many reasons for a toothache. Early cavities usually don’t cause sensitivity, but gingival recession that exposes the root surface of a tooth can cause fleeting (if significant) sensitivity to cold. This can be treated with a fluoride varnish, bonding, or a gingival graft.
Deep decay or trauma that affects the nerve in the center (pulp) of the tooth tends to cause lingering sensitivity, especially to heat, and spontaneous pain that can wake you from a sound sleep. This type of pulpal inflammation is irreversible and will need either a root canal or extraction to remove the source of the pain.
Cracked teeth are associated with pain on chewing, especially on release rather than closing. These situations require a full coverage restoration (crown)
These are just a few of the causes of tooth pain. Dr. Forgosh uses a combination of your symptoms (what you feel), signs (what he can see), and the history of the problem to develop a proper diagnosis. He will discuss the problem with you and help you decide the best course of treatment.