Lynn, I have relatively small hands and fingers. I have noticed that when playing in half position (say in the D string in this example) My natural hand spacing does not cover the spacing of the notes. For instance Eb might be in tune but to play E and F in tune I find myself having to slightly pivot or shift up a bit. any sort of stretch is uncomfortable and creates a great deal of tension in my left hand. I don't know if this is a common problem for bassists with shorter hands, but it can be frustrating for me, particularly when I want to play 5th or octaves in tune. Any help you have on this issue would be greatly appreciated.

Here are some factors to consider that may help:
Keep the left hand thumb opposite the fingers, not stuck up like you are hitch-hiking. Some say the thumb naturally falls between the first and second finger, and others advocate having it opposite the second.
Keep the thumb behind the neck, not sticking out the E string side. Check to see that you are not in contact with the back of the neck with your left palm, with the thumb instead.
In a mirror, look to see that your left hand fingers are perpendicular to the strings and not pointed down toward the end of the fingerboard.
These previous things allow the fingers to open up more naturally.
The scale of your bass may be too large for you.
This is a question that is challenging to answer on the internet without seeing you play. Consulting a private teacher may help.
Good Luck