I have just recently evolved my tyrogue into hitmonchan,and it now punches anything in sight at random. Is it common for it to do that?

I’m afraid so, anonymous, especially for newly evolved hitmonchan. The entire line is known for their eagerness to train and fight, and hitmonchan especially is not only proud of its punching but also the most determined out of all three tyrogue evolutions. Just as you had with your tyrogue, you’ll need to maintain a daily training ritual to alleviate his new urge to punch everything and to maintain his overall mental health. Likewise, always make sure he has something sturdy to punch…

…and maybe avoid standing directly in front of him or within arm’s reach.

Good luck!