Shield board with holes, do I need to solder? I have a motor shield.
I can put it on top of my arduino Mega and works perfect.

However, since the shield plugs in on top of the arduino board, I don't have access to 5V and GND from Arduino Mega.

I just have holes on the board with 5V and GND. (look at image)

Do I have to solder a cable there to have access to 5V and GND? or there is another easier way?
Since there are two grounds, a 2-pin terminal block of the type already on the board may fit. Or, since the shield doesn't obscure the far end of the Mega (the end with the high numbered I/Os), you could pick up 5V and Gnd there. The ends of the double-row female header have respectively, 2 each 5V and Gnd connectors. You would pick those up with breadboard wires, though it is admittedly less secure.