Unfortunately, like many things in modern Judaism, the topic has been hijacked by the haredi/right way elements in Jewish leadership. It is important to get a good overall analysis of the subject.
A Modesty Proposal: Rethinking Tseniut by R. Marc Angel
A New Analysis of “Kol B’Isha Erva” by R. David Bigman
More on Kol Isha by R. Michael Makovi
A History/Developement of Women’s Hair Covering PDF by R. Michael Broyde
Sources for Jewish Modesty PDF ADVANCED compiled by R. Josh Yuter