about home button doing a little bit noise

my iphone 5 when i bought it from virgin megastore from lebanon so it has been with me about 3 months ago so i noticed that my home button is doing a little bit of noise that you cant listen it only if you put it in your ear but its still working the button but its so strange i see another of iphone 5 and i dont listen that ticking from them so i want to ask is it normal to do a little bit of noise before pressing the button for my new iphone 5 and please i want a reply just to know