this could be several reasons, 1. after a number of usage, the internal wire at the very end junction of the EarPods may be isolated, damaged or break apart do you to bending and folding during usage. 2. the other reason is also use of max volume could also damage the EarPods, since EarPods work with a vibrating of magnetic coil. as we use high volume, the coils required to jump to the very end of top and bottom of the magnetic field.
yes, you can buy the lcd from ifixit website. go to the website ifixit.com select ifixit, select shop for parts, then buy the part that you want. you can also buy the parts from your local stores, or ebay, amazon and alibabas. thanks
well, restoring the phone and sim card has nothing in common, however after a restoration is done on iPhone it needs an active and valid sim card to activate the phone and to bring it to a working condition. for example, if you restore an iPhone 5 which is from at&t, to bring it up to a working condition or to pass to the normal home page you will need an active at&t sim card or sim equivalance ( any sim card that work on at&t phones). thanks