IPhone will not respond

Question

A few days after updating to 7.0.3 I was using my iPhone 4s to listen to music, and noticed it was unresponsive when I pushed the home button(as well as all of the other buttons). I performed a hard reboot that stopped the music, but the phone didn't come back up. I tried this several more times with no success. I then connected my phone to itunes and of course it wasn't detected. On my drive to work I tried a hard reboot again this time with success. I continued to have problems for the next couple of days before they went away, only to return again today more than two weeks later.
So after my initial problem I noticed that my cell service was searching every time I woke the phone up from being idle. Now if I proceeded to make a call suddenly the service was restored. I also had problems with the phone going to sleep and not waking up unless I performed a hard reset.
I'm now once again unable to power up or hard reboot the phone.

Answer 1

My phone suddenly stopped working last night as well. I have tried every solution (hard restart, DFU mode, plugging into the computer and holding the home button, etc..) provided online and I cannot get it to respond. My lock button and home button have always worked perfectly, so those aren't the problem. I did notice right before it died that when I was attempting to open my messages app, it would lag really bad to where I would have to close the message app and reopen; I then thought to restart it, so I held down the lock button and home button; the phone restarted but all of my messages were missing; then about ten minutes later I went to unlock the phone as normal, and it blinked on and then sudden blackness. Now it's not responding to anything and I can't get any of the remedies to work.