My wifi wont switch on on my iphone?

For some reason im not able to turn on the wifi from the options on my iphone. Its literally greyed out and i dont know what to do. Its annoying please help!

Which iPhone and which iOS? IOS 6 has known issues with that exact problem http://www.zdnet.com/apples-ios-6-wi-fi-problems-linger-on-7000004799/ call or visit apple support, or your carrier!

Mine is doing the same exact thing and i took it to a few stores and no one wants to do it?

Same here its greyed out and i tried turning off my phone and turning it back on and still nothing happened i even tried to rest the network settings. I really dont know what to do at this point. Can any one help?

Same here. Cannot figure out what to do:(