Chosen Solution
My volume won’t work with headphones in. It sounds like a very faint whisper when listening to music and when I take out my headphones YouTube makes this loud buzzing noise and I can’t hear the videos. And the volume only works half the time on snapchat.
You iPhone 6S is still under warranty, take it to your local Apple store first. Sound like the headphone jack was damaged or manufacture defect. Don’t void your warranty by trying to repair it.