in my iphone6 only one side of my ear phone works that is the left bud whereas there is no sound from right bud

its been two month since i brought my iphone6 initially the audio was good it worked well in the both the sides of earpods but suddenly the audio was audible only from the left ear bud and whereas there is no sound from the other i.e the right one

i have checked my settings equalizer was also in the center position but there was no sound from the right one so then i had done reset to my phone and then the audio worked properly from both the sides of my earphones and again the sound stopped working from the right ear bud so i had repeated the process of resetting my phone yet the problem remained same what should do now?