Is it possible to change pitch of a song or vocals without the chipmunk voice?

If you have a transposition chart you can. I use one all the time for guitar and piano.

There are certain programs you can use to change the tempo on a recording as opposed to the speed (which affects the pitch). However, don't try to change it too much - the recording can quickly become sterile and digital sounding if the pitch is adjusted too far.

If you mean change the key the music is in, there are advanced equipment used in recording studio that can change any and everything about a song, it juts depends on what you want, how much you want to spend to do it.

If you mean for you to sing a song, that is easy, you merely transpose the music into another key.

Is there any free software, what can change the key of the vocals?

Yes, it is possible. Vocals can be transformed in low pitch or high pitch. You will find many of these videos on You tube. Hope you got your satisfactory answer!

And I still want to know that it is possible to change the key of a song without the chipmunk voice?

And I still want to know that it is possible to change the key of a song without the chipmunk voice?

Yes. Answered above. Use a transposition chart. For example, If the song is in C, transpose to a lower A, G or F. You do know how to read and transpose?