After some experiments, I found out that in my program if I wrote "boost::" it autocompletes but "unordered_map" does not exist in the autocomplete options. But I have included the header and I am able to navigate to the file by right clicking on the include. I also see that things that auto-complete are not causing compilation failures but ones that dont auto complete do cause problems.
I am sorry if this does not have too much significance, but since this is my first time coding in Windows/Visual Studio after coding in Linux, was thinking this might be a clue to the issue.