I wouldn't call yourself 'Shingle' if I were you, because 'shingles' is the name of a nasty painful illness.
There is really no such thing as a 'legitimate name', because, unlike in some cultures, English-speaking countries don't have official lists of permitted names and tend not to have rules and regulations regarding names. Within reason, you can call yourself what you want.
But if you want a name that sounds like your own name, there are plenty of conventional names. Why not go down the route of Sean/Shaun/Shawn, which are spelt differently but all pronounced the same. They're the Irish form of 'John', and very common in all English-speaking countries. Presuming you're a guy, that is - your profile doesn't say. If you're a girl, come back for more suggestions!