I'm 23 and I've never had a cavity in my life until last time I went for my checkup. I have 8 freaking cavities in my mouth? I brush the same as I always have.

I've also had problems with muscle spasms, ,sore neck, headaches, lumps in my throat, pain in my neck and wonder if there is something wrong or some kind of deficiency in my body that could also cause my teeth to rot.

I seriously doubt that your tooth decay and other problems are related. I often see folks in your age range present with increased tooth decay. Usually this is due to diet. Young adults tend to change their diet patterns after they leave home and often consume more sugary foods. The most common culprit is drinking sodas in between meals. Even diet sodas are acidic enough to cause tooth decay. Regular tooth brushing is great but daily flossing is far more important. The tooth brush can not clean the plaque between teeth; the most common areas for decay to occur. Cavites often take several years to develop to the point where they are detectable visually or by x-ray so you may very well have had them a long time. My suggestion to you would be to have your cavities fixed up then concentrate on brushing and flossing. I'd also recommend that you use a flouride rinse nightly, this will help prevent future decay. Good Luck!

Muscle spasms, sore neck and headaches could indicate that you have TMJ which is a misalignment of the jaw. It can be caused by either stress, tooth grinding, poor dental work, or injury. Hopefully, you don't have it but you might want to discuss the possibility with your dentist.

Good luck