Why isn't my Iphone home button working?

I have an Iphone 5s. The problem with the home button is that it works but doesn't work when I'm trying to unlock the phone. If I get into my phone and I use the home button, it is perfectly fine but when I'm on the lock screen, the home button doesn't work at all.
I have the latest (i think) IOS update where you have to press the home button to get to the passcode instead of sliding the home screen like before. Right now I have to slide a notification to get to the password and it is a huge inconvenience.
Please reply As soon as possible.

Is an iPhone 7 worth upgrading to?

I currently have an iPhone 6S+, 64GB, my service provider has offered, an iPhone 7 32GB with 20GB of data included for $85 a month. I'm currently paying $110 for my phone now.
Should I upgrade?