Why my iphone flash is turning on itself?

My friend, as far as my knowledge goes the iPhone exhibits such sort of behavior of shutting itself down and freezing itself when you have jailbroken the phone. Jailbreaking an iPhone is always regarded as very risky since anything can happen to your phone at that point of time and you would not be able to solve it since after jailbreaking your phone you have seriously severed your contract with the carrier.

Now since you have not mentioned anything in your question pertaining to jailbreaking your iPhone, then I think it is a problem with your handset for which you should send the handset back to the Apple center so that they can handle the problem. I hope the iPhone problem gets resolved as soon as possible. Good luck with it.