Audio output: can't set my headphones as my default audio device

I've been having this same trouble for months--only with Premiere Pro; not with any non-Adobe apps.  Please help!  15" SurfaceBook 2, Premiere Pro CC.  When I'm working in public places I'd like to monitor via [1/8" analogue plug] headphones; when I'm home I'd like to be able to just hear audio via the built-in speakers.  The expected behavior: No headphones plugged in, sound comes out of the speakers; plug headphones in, speakers turn off and sound comes out of the headphones--right?  What I get is, often the sources are switched around.  With headphones plugged in I have to select "Speakers (Realtek High Definition Audio(SST)" from the Windows pop-up menu at bottom right, for the headphones to get sound.  BUT... if I want to adjust the headphones' volume, I need to go to that same pop-up menu, switch over to Headphones, adjust the volume on the software slider, then switch back to "Speakers" to hear audio at the new volume.  And vice-versa: if the headphones are still plugged in and I wish to hear audio through the built-in speakers, I have to select "Headphones" from the Windows pop-up, while adjusting volume with the "Speakers" pop-up slider.  It gets worse: sometimes (like just a few minutes ago), I am forced to go into Premiere's Audio Hardware preferences and select the "Default Output" to get sound.  I'd been using headphones at a café; came home, set the computer up with no headphones attached, got NO sound until I selected the speakers through the preferences.  Truly would like to have simple, expected functionality!  Suggestions...?