my iphone has a wifi problem

well anywhere i go , i mean anywhere i go my iphone doesnt find any wifi networks at all , even in my own house. its not my router because everything else is connected to it and works fine but ! one day i went next to my router and my phone actually found my house network ! but i moved to the next room or even 5 feet away and its gone. how do i fix this ? i reset network settings, i did everything possible . i recently got the color of my iphone changed, but i dont think it can be anything inside, well can it? i really dont know where to go from here , if anyone can help PLEASE write back ! or skype me - JMS , thanks