I am looking for really good drama that does not involve any murders, killings or characters who spend their time solving them, also, in general, characters who are not in police, law or doctors. ML/FL who do not have mental health problems or past life problems. 

just watch romantic/romcom dramas

here

  It does sound like romances would be your best bet, but here are some suggestions for Dramas with minimal/no romance and no criminal investigations either.

https://mydramalist.com/16585-juhan-shuttai - work

https://mydramalist.com/18938-ie-uru-onna - work

https://mydramalist.com/679-shinya-shokudo character tales

https://mydramalist.com/search?q=arc+of+life work, sisterhood

https://mydramalist.com/15852-yeah-thats-how-it-is slice of life

https://mydramalist.com/28051-parting-life female friendship

https://mydramalist.com/31183-keep-going-you-re-the-best slice of life

Unicorn (a comedy workplace drama)

Be Melodramatic (friendship and comedy; I don't think any character has a dark past or anything like that)

That type is easier to find in cdramas/jdramas than kdramas but possibly Tomorrow With You (there are some problems but none of the other things you mentioned).

There's also some short dramas that perfectly fit what you're looking for: