I think choking up on certain songs comes as a result of something in that song that touches you on a personal level from your own life experiences. For example, I met my wife on a Sunday over 40 years ago and, to this day, if I sing Nat King Cole's "That Sunday, That Summer", that does it for me. In fact I can't get through the song.
My dad and one of his sisters were professional opera singers and there are many arias that will have the same effect on me whenever I hear them.
These are the true beauties of music. It touches inner parts of the soul that so often are taken for granted or that we are perhaps even unaware of, yet the music will get straight to core.
We are blessed.