Garz
Retired Moderator
It's most likely coil wine. For some reason some iPhone sevens are louder than others. If you listen really hard you can hear it on any iPhone, or most electronics. It's the processor under load creating unfortunate acoustics.
If it's allowed enough to annoy you, absolutely go to Apple and have it swapped out.
Seeing it first hand on my wife's first 7 plus, this clicking/creaking sound is no coil wine. It has nothing to do with the processor. I'm assuming your referring to that hissing sound that has been mentioned.