So I've had my iPhone 5S for over a year now and other than having to replace the LCD due to me dropping it, I haven't had any issues with the phone. Last month I went to use my phone and I noticed it wasn't on. The battery had at least 50% left and when pressing the power button to turn it on it wouldn't respond. After repeatedly pressing the power and home buttons about 4 or 5 times the phone booted up and behaved normally. It never did it again until this past Tuesday. So on Tuesday the phone did the same thing but this time it continued to die even after I rebooted it. I would check Facebook, Twitter, use Safari, etc. put the screen to sleep with the power button and within a span of 5-10 minutes I would go back to use it again and it wouldn't respond. I had to use the same procedure I did the month previous and repeatedly press the home and power button until the Apple logo would appear. Now here is the crazy part... if I am using the phone at work and stream music all day long the phone doesn't die. It's only happens if I use it a few times to check apps and then lock the screen on the phone. If I don't use the phone all day it won't die either. Yesterday I streamed music all day and it was fine when I left work until I stopped using it on the way home. Sure enough, phone wouldn't respond to any inputs unless I did my procedure. Any ideas on what is going on? CoconutBattery says the battery has a capacity of 90.6 with 300 load cycles. Am I looking at a new battery? Phone is out of warranty and I don't want to spend tons of money to get it fixed. I have an upgrade, but I would rather not use it. Any help would be greatly appreciated.