I have to hold my charger at an angle to charge my iphone 5 and its not working properly why?

Do you know anyone with an iDevice that uses lightning cables? If so, you should borrow their cable and see if it works with your phone without all the hassle before immediately concluding that it's the phone. I know previous cables of mine have done that very thing, merely because there was a short in the cable. If that still doesn't work right, then perhaps it is the charging port.

Tr cleaning the charging port. Inspect it with a bright light and magnifying glass (if needed). Clean it with a wood or plastic toothpick. But it could also be a bad cable, as bcoop17 suggests.