Things hidden under the grid - Tradução em português

Hi guys I'm looking for the meaning of this sentence.

I know what grid means, but how people can hide things under it?

Is there any different meaning for grid? Besides "grade" ou "grelha"?

https://goo.gl/LZDLMd

"When I was a kid the things I did were hidden under the grid
Young and naive I never believed that love could be so well hid
DWith regret I'm willing to bet and say the older you get
It gets harder to forgive and harder to forget
It gets under your shirt like a dagger at work
The first cut is the deepest but the rest still flipping hurt
You build your heart of plastic
Get cynical and sarcastic
And end up in the corner on your own"