I have discovered a tried and true method of testing whether the volume on my headphones is working:
Step 1: turn your volume to max
Step 2: go to the following page: https://www.youtube.com/watch?v=rxJ-cvcz1BQ&index=77&list=PLMBYlcH3smRzXGvi1NxF4qIXOWh9R_qbw
Step 3: let the video start playing
If you can’t hear anything through your headphones, but hear perfectly fine without them on, then you need to get new headphones.
If you can’t hear anything through your headphones, and the problem persists after you take them off, then they’re working just fine.