ddiddler....Pain from practice is a problem that bears close watching. Left unchecked, it could even derail your playing guitar. Since you are just starting, you can probably avoid that pit fall. It is easy to get all contorted while trying to learn guitar. This is an avoidable problem and you are looking in the right direction to slove it.

You might try playing in front of a mirror, so you can see you finger placement without looking down. Repeating the same bent postrure everytime you play the guitar could be a path to problems.

Maybe go back to some simple songs that you can approach playing without looking at your hands. My PT got me to do that as a way to improve my postrue when I practiced. It helped me deal with my own bad habits.

John.... I think holding your guitar down around your knees was popularized to look cool (fashion over function). Maybe a complete finger picker, like Jeff Beck, gains some advantage from a lower hand position. However, he does not use that low position, but rather he uses a mid height guitar position. If you watch the good players who use a low guitar position, you will see many of them lift their ax up by steping one foot on a monitor box when they play lead.

I used to play with a low guitar position. That was one of the frist things I had to lose when I started to develop physical pain from playing guitar. It worked for me.