Why would my 6 year old son have a really bad toothache?

Broken, infected : Toothaches occur for a variety of reasons and can happen in teeth that have either decay, are broken or are loose. Either way, he needs to be seen by a dentist and treated for the toothache.

Hard to know~: Teeth can hurt for several reasons. And it's not always a tooth problem. You'll need to see a dentist to figure out what the problem is. In the meantime, keep the tooth and the gum around it clean. Do not put a hot pack or an Aspirin on the tooth or his face as these can lead to serious problems.

Infection: Tooth pain in a six-year-old is likely due to an infection. The infection may be in the tooth or the gum. You should take him to a dentist for an examination and necessary treatment.

He has a cavity: If your son eats lots of candy, and likes to drink soda, or eats lots of desert, and chocolate (anything that has sugar in it) and is not dilligent about brushing, then he will have developed a cavity. Don't worry though, this is his primary teeth, and will shed them and get permanent ones. However, the cavity needs to be cleaned and filled by your dentist (or pedodontist--kids dental specialist).