I believe you might be on to something.  You think there is a reason why TED talks are given standing?  Why speeches are delivered standing?  

I'm sitting (in a decently comfy chair) with my chin up.  I have my monitor above my eye level (just slightly) so I can get my bifocals into play as needed.  It's decent if not good posture for communicating with people I'll never see.  

When I talk on the phone I am head up.  I generally put it on speaker so I can assume good posture.  When it's an important call I stand. Even when I text it is more head up than down.  I never learned that quick thumbs thing, and I spell my words out.

Not that I have thought that stuff out, but I do consider cause and effect for most everything.

I've put a considerable amount of thought into how I sit on a motorcycle.  For going long I want to be just slightly forward of straight up with a little pressure on my arms and my abdomen helping with body strain.  I want my feet directly under my hips (not that ridiculous feet forward position favored by the 'bikers').  Optimizes control and reduces travel stress.

So, yeah.  Posture counts.  Maybe you can parlay your leg discomfort into a massage or rub?  You never know unless you ask...