Why does my phone discharge when plugged to any USB port?

[specialagent]

If it's plugged in to the charger, everything's ok but when I connect my phone to any USB port (from any computer) my phone doesn't charge, the battey discharges more slowly but doesn't charge at all. Thank you

 

[Sophiania]

If it's plugged in to the charger, everything's ok but when I connect my phone to any USB port (from any computer) my phone doesn't charge, the battey discharges more slowly but doesn't charge at all. Thank you

And if your device can be recognized by computer? Maybe one of the pins of the charging port that in charge of connecting with computer is broken. You can check if the charging port got any damage.