Most likely wearing a Blair witch symbol means you're a fan of the movie or you think it looks cool. Some websites claim the symbol is an obscure charm used by occultists and alchemists, others claim...
The spelling "wich" is not a word, so I'm afraid your riddle makes no sense, even as a riddle. The only correct spellings are "which" as in "which one", and "witch".
I am a witch. ----- There are many witches out here, far too many to have every one of them answer here. ----- ANSWER there are thousands of witches, Wiccans and pagans and all sorts of other people...