Something I have heard a bit in my days of being a geek.
So, above, is a very simple instruction from Apple on what to do if your iPhone (this works on all similar iOS devices) is misbehaving. You’ll be surprised how many issues are resolved with this little trick.
There is one other thing that you can do yourself before asking for help and that is to check that your software is up to date. Here’s some advice on how to do that: iOS Software Update.