I have a Nexus 4. I got it Sept.02.2013, I am noticing that my phone is not charging very good. I am not sure if it is the charger port on my phone or cable that is doing it. is it expensive to get the port changed in my phone? or am I still under warrenty it has only been 9 months
You should try using another charger, that way if it works, you know the issue is with the charger and not your phone.
If it is your phone, broken charging ports are usually considered Physical Damage instead of a defect and as such, the warranty won't apply. You can still have koodo get you a repair estimate but normally repairs may cost as much as a new phone.
Optionally you may find a fix it shop somewhere near you. These places have been popping up everywhere. It may be cheaper to have them do the repair for you.