Why did North Korea fire a missile? Is this a sign of war?

That we now have a wimpy pansy administration in place and all the cowering they did because Trump was a Strong President is over.

they just want to prove that they have the confidence to bite back against the U.S, but wont invade south Korea.

They are mad that their American appeaser has been voted out of office. 

No, it’ll be alright. (MOST LIKELY) North Korea is just testing to see how the new administration will react to the missiles being fired. 

they did the same thing when Trump took and Obama before him.  It is their way of seeing how the new administration will react and what they will do.  Unless Biden does something really stupid it will probably work out the same as it did that last two administrations.  We will offer to negotiate rather than attack them, and it will turn into a year or two or three of talks until they reach an agreement that works for both countries.

All the US presidents get tested by our enemies during their first months. North Korea wants to see how the US will react. 

They are testing to see how Biden will react.

As for JoeBama's response . . . North Korea launched missiles 26 times during the Trump presidency.  The first was March 6th.

Their missiles are like bottle rockets you can set the angle and you know how far it goes but you can't aim it exactly to a target.  

Nope.  North Korea continued to test missiles, repeatedly, after Trump's useless photo op with Kim.  In 2019, NK launched missiles on May 4 & 9, July 25 & 31, August 2 & 24,  Sept 10, Oct 2 & 31, and Nov 28.  Some of those days had two launches.  Remember when Trump promised he had made us safe from Kim Jong Un's missiles?  Did you believe him?

No just testing the senile old guy in the White House, no one has told him yet that they tested medium range missiles.