@babycat
Two other potential causes of “burning mouth syndrome” that are not discussed frequently and are not typically associated with burning mouth are:
1) Certain mouth washes such as Listerine can cause significant burning.
2) If someone consumes a lot of pine nuts, especially those from China, they may experience Pine Nut Mouth Syndrome which can result in a metallic taste lasting days to weeks.
For both of the above, the easy solution is stop thise products.