Usually pain is a sign of an infection. Sometimes jaw pain can be a TMJ problem. Google TMJ. See a dentist.
Does tooth pain that spreads to your jaw, mean that you have a bone infection? or something of that nature (instead of just a cavity)?
It could indicate a number of things .. A damaged tooth (from a cavity, or injury) may result in pain caused from an exposed nerve. Even just simply 'sensitive' teeth caused from thinning enamel can cause pain. Jaw pain can be cause from irritation to the nerve inside the tooth .. and of course, if left unattended infection is likely to start. Jaw pain can also be caused from tooth impaction .. which means the teeth are too crowded and are not setting in place properly because they become restricted .. Wisdom teeth often become impacted .. and can cause a lot of pain.
It is always recommended to see a dentist regularly to monitor your teeth and control the growth of cavities and gum disease .. There are toothpastes that help to manage sensitivity pain like Sensodyne (for example).
Well, yes, but that usually wouldn't be at the top of the list of possibilities.