They are a little bit different. If you are working on something and another thing catches your attention, you can say that you were distracted. Examples: - I was distracted from my homework when a pretty girl walked by. - He would not be good for the project because he is too easily distracted. So, being distracted means that you lose focus on your work. Being sidetracked means that you've just decided to move on to another project from some reason or another. Maybe something more important came up. - I didn't end up finishing painting my car, because I got sidetracked with a brake job. - We were going to rake the leaves, but got sidetracked with a bunch of other projects. Hope this helps!

As far as I know, "to sidetrack someone" is to distract him/her from an important matter. So normally they are synonyms which you can use interchangeably.

Those phrases are quite similar but "to get distracted" is more psychological like you lost your ability to concentrate on something while "to get sidetracked" is often used in a more physical way. Examples: I tried to get some work done but did not do so well because I got distracted by an interesting news report on the television. I was going to go out but I got sidetracked by all of the chores I had to do at home so I never left. They are not so different, so don't worry if you use them interchangeably :)

Las dos respuestas son correctas. Not sure if my Spanish is correct, but both answers are correct.