In this case, Katherine was experiencing pain in the neck because she has been many hours working and she is stressed.

You should relax a bit.

You should rest and take some breaks from time to time.

You should meditate, go for a walk, sleep more, do some exercice, etc

You must organize your time better.

You must go to the doctor if your neck hurts.

You must take breaks every 30 minutes that you are studying.

He is anxious and depressed because he doesn't spend time with his friends and instead he is playing with the computer.

You should spend less time playing computer games.

You should spend more time playing with your friends.

You mustn't play computer games mopre than an hour per day.

You must go out with your friends and do outdoors activities..

Aroa has started eating in front of the TV and PC in lockdown, and now she can't stop doing this.

Aroa should find another hobbies, Aroa should not watch too much TV and PC

You must go out with your friends,

You mustn't watch TV while eating

Victor is suffering bullying from somebody on the Internet. This affect in his health because he can have some mental health problems.

Victor, as a friend I tell you: You should that you can search for help and report the staker.

You mustn't use the internet for a week. We must go to report the stalker.