Visually inspect the phone's USB charge port with a strong light and a magnifying glass.
Verify that all the pins are there (5, especially pins 1 & 5) and that they are all straight and parallel with each other.
Check that there is no lint or dust lodged in the USB port. If so, DO NOT use a metal probe to try and get it out. Try using a vacuum cleaner to suck it out. If this doesn't work try gently (so as to not damage the pins) using a wooden toothpick.
If the USB charge port appears to be OK, insert a USB cord into the port, (you can leave the other end of the cord unplugged) and gently try to move the plug from side to side to check if there is any movement in the USB port. If it feels loose it may have become disconnected from the systemboard. If so, as it is a SMD (surface mounted device) type connector, you will need to have the requisite skills and tools to reconnect it to the systemboard. This is not a job for novices. You can cause more damage than what you started with if you don't know what to do.
If this is the case I recommend that you contact a reputable, professional mobile phone repair service and ask for a quote to repair the phone.
Hopefully this is of some help.