Q: The volume on my iPhone 5s isn't working: any solutions?

When I'm listening to music, I turn it up to full volume and I only hear a faint sound. When I put headphones in, the iPhone doesn't recognise it and doesn't say high volume, and I still only here a faint sound. Is there any way I can solve this issue? Or will I need to take it in for repair?

Also when I turn off the ringer and I plug in my phone to the charger, I only feel a slight vibration and not two vibrations... is there something wrong?

Thank you.