If there's anything good to be said about a broken tooth, it's that the problem is pretty obvious to the eye. The same can't always be said when the tooth develops an invisible crack.
The potential for cracks comes with age. Past 40, enamel tends to grow brittle partly due to reduced moisture within the tooth structure. The tooth itself is less resistant to stress, and teeth with numerous cavities or that support large restorations are more prone to cracking. Molars are prime candidates for this syndrome due to the tremendous stress in that area of the mouth. But other teeth can develop fractures as well. The most common cause is an accident, like chomping down on a hard foreign object. You are more at risk of cracking a tooth if you endanger your teeth with bad habits like ice chewing.
Diagnosis of cracked tooth syndrome is sometimes difficult, because it can be present in an apparently normal, cavity free molar. Often pain emanates from the entire mouth area, not from any specific tooth. Always let us know if you have pain that isn't associated with decay or injury.