Rear light turns on only after closing boot? 2011 Polo GTI

[hng049]

Hi guys. Just need your help on this matter. Every time I turn on my car the light bulb shows up on the dashboard. My left rear light isn't on but when I open the boot then close it again, the rear light turns on. This is really bugging me since I have to do this every time I use my car. Is there a loose wire or does the bulb need to be changed? I had a look at the wiring for the light but nothing stands out, I've jiggled them too and they feel solid in the sockets. Do I need to take it to a mechanic? Thanks advance.

[Umai Naa!!]

Replace the bulb, and check the terminals.