Throwing across body

Do you throw againest your body if you rotate until your back is almost facing towards home. I do this and have no soreness in my arm.

Throwing against, or across, your body happens when you stride closed. This means that instead of stepping towards the target you dont quite get all the way there. Imagine standing facing towards home as a righty if your foot was to land between straight in front of you and to the right of you you would be throwing across. Your load has nothing to do with throwing across your body but it can sometimes hurt with timing when you are young. I believe this is what you are getting at?

To take it a step further—something like that happens when a pitcher uses the crossfire, which is a move that works only with the sidearm delivery. What you do is take a step toward third base (if you’re a righthander), whip around and fire the ball to the plate from that angle. I remember when Ewell Blackwell used it extensively, and I picked it up and worked around with it. Being a natural sidearmer I took to it, and I absolutely fell in love with it—I remember one day when Ed Lopat was helping me with my circle change, and he said to me "I know you’re going to crossfire it—you use that move with everything you throw."
I know that there are some coaches who don’t like the idea of throwing across the body, but if you’re a sidearmer and can use the crossfire, go to it. It’s another way to discombooberate the hitters. 8)