CANKER SORE ON THE BACK OF MY THROAT

[Luis818]

I have had my braces for about 2 weeks now. I have a really bad canker sore in the back of my throat. Its really painful every time my throat gets dry thats when it seems to hurt the most. I bought Colgate Orabase it seems to be helping some what. My concern is that I dont understand why the sore is on my throat wich is no wear near my braces and not on my cheeks, lips or gums. Has anybody experience a canker sore on the throat. The only thing i could think that might of caused this is when I brush my back molers the tooth brush bristles might rub against my throat and irritate the tissue back there.