My iPhone 4 won't charge unless its turned off

I have been using my iPhone for the past three years. It had no issues until it stopped charging. I have been always using the cable and charger that came with it. That same cable may be worn but it is still working proven that it can still charge my iPad. I tried cleaning up the port in the iPhone but it still doesn't work. I have notice though that some of the pins were pushed back compared to the port in the iPad. What might have caused this? How do i fix it? If I can't, where do i get it repaired?