Joey is correct, if you want to pause the sound, the Set Paused function in BluePrints is the way to go.
However, one thing you will need to keep in mind is that your sound is being attenuated. The Audio Engine (as an optimization) culls away sounds that reach 0.0 volume, so when you’re exiting the range of hearing your sound, you will need to add one more thing: You will need to turn on sound virtualization for both your project and the sound you want to make an exception for:
Project settings:
And Sound Wave details:
And then create some triggering condition so that when the player is in range you unpause and when the player is out of range you pause.
You could do that by actually measuring the distances like so:
Or you could use a more traditional trigger sphere (or other shape) that is the exact same size as your attenuation fall off and just trigger events when the player enters or exits the trigger box:
