Debugging specifics wrt visual studio

I was having problems debugging with visual studio 2015, where even
with all the relevant modules loaded and their status being "Symbols
loaded", I was not able to set any breakpoints from the source file.
This was happening even in WinDbg. I wondered if the pdb files even
had the sources specified. So I found code for a tool which is
essentially a pdb parser. On building and running it on any of the pdb
files, I found that there were no sources for all the object files,
related to lo, in that module.
I then downloaded vs2013 and built with it. And on inspection of the
pdb files, I found that the sources were now being specified. I was
also able to debug properly.

Has anyone had similar experience with debugging in vs2015 without
vs2013 being installed on their system? Better still can anyone shed
some light on why this might be happening?

Regards,
autoit