Problem with low voice volume through headphones with volume on high

I recently replaced the headphone jack and charging port in my iPhone 6, I was having connection issues with the charging port. Now, the charging port works, but I have low voice volume on phone calls and when watching videos. When using earbuds, background music volume in videos is loud, but the person speaking in the video is barely audible over the music. If I disconnect the earbuds and listen using the loud speaker, then the voice volume is correct. Also, while trying to listen to a phone call, the person I am speaking to is so quiet, I can barely hear them, but if I put it on speakerphone, they are loud and clear. I also found that if I go into settings to the same place you go to adjust for hearing aids, and move the volume balance bar off of the center position between left and right, then the voice is easily audible when playing music and videos, but not on a phone call. Any help to remedy this would be greatly appreciated!! Thanks for your time.