I periodically have this issue with my headphones forcing me to buy a replacement every 1-2 years. Usually headphone cable is to blame - in addition to trying another headphones try sound from other sources (music players, other games, etc).
If your soundboard is an integrated Realtec there’s usually a Realtec HD utility installed together with MB drivers, sitting in your tray. There’s a general “test” button for speakers in it, it sends sound signals separately to the left and right channel in turns. Try it - if one side is “deaf” it’s usually either the cable contact or the headphone itself.