As suggested by our fellow members above, try to replace the cable first since this would be a cheaper option and if it's still the same try taking the phone to a repair shop and see if there's anything they can do to fix or replace the connector.

I think your USB cable is loose
you should buy a new USB cable
there is no faults of your cell phone
with regards,
Kautuk

Something is either wrong with the connector on the wire or the phone. Try replacing the wire and see if that helps. If not then there is nothing you can do other than get a new phone or have the old one repaired.

My USB cable often gets detached from my phone. It only works when I hold it tightly. Please help.