Never had this problem. Maybe, try to put the phone not too close to your ear?
Fix for additional line, I had the same problem until I realized I had the killswitch for Camera & Microphone ON! So turn it off 
Never had this problem. Maybe, try to put the phone not too close to your ear?
Fix for additional line, I had the same problem until I realized I had the killswitch for Camera & Microphone ON! So turn it off