(New) Apple Headphones Uneven Sound

So you see, with my iPhone 5s, i've got new apple headphones, they're a different model than the others, a bit modified. But what's happened is, after 5 or 6 weeks of usage, i plugged them in, and then i noticed a problem. The "R" had a lower volume than the "L", but then I plugged it in to my PC (Monitor) and it was the same deal. I honestly didnt know what to do so I came here, please, someone help me 😟