Women have it easy when it comes to fashion over men when they are singing, and that showed when I found myself wearing a shirt that was a little too tight on the collar, because it interferes with my singing, especially when I am wearing a tie!
Of course, the difference probably is now that I am more generous in collars. While I am officially a 15 1/2 collar for my shirts, I now prefer wearing at least 16 to allow for more leeway in the neck so I have more room to sing without the collar "tightening" the pipes when I sing.
The menswear person said I was a 15 1/2 collar, but it was a little uncomfortable for me, and I prefer the 16 when I sing.
Of course, when you have both 15 1/2 and 16 collar shirts, you find yourself preferring the 16's because they don't interfere with the neck, especially when you're singing. All recent shirts I have purchased are 16 because I prefer that size, but I found an old 15 1/2 yesterday but somehow I forgot that was the tighter size when I wore it to sing, and I could see where I was having problems!