for what its worth, sounds like you need a shorter stem. 1.5 inches below seat height is not low by any means, but from my experience, the reach plays more of a part with neck , shoulders etc.
the one thing I would suggest is to forget about what anyone says about what "should" fit you and get a stem that is a couple of cms closer--which I just figured out is about 3/4s of an inch....
I would however try to ride another bike with diff dimensions, or rather a even shorter reach, so you can compare your bike to it to see really how a given measurement changes how you feel. Even a short ride, especially if right after being on your bike as it is, will give you an idea.
Not that this is your case as you have straight bars, but thats the big advantage to drop bars, because when a bike/bars are properly sized to you, the different hand positions really do allow for more changing of hand positions, which is always better for comfort---BUT the reach still has to be right for the individual. My present bike has a reach almost 2cms closer than my old bike, and it made all the difference--AND the new bikes bars are lower than my old touring bike, so it was teh closer reach that is the real kicker for me.