Never any serious arm injuries. I missed a couple of weeks with some bicep tendinitis but that was it.
I pitched all through my baseball career from little league to the big leagues. While pitching wasn't my primary position until college, I did pitch when needed throughout spring and summer leagues in my youth.
It wasn't until college that I got into a pitching program that included a consistent throwing, conditioning (distance running and sprints) and workout routine. The program helped to increase my velocity and keep my arm healthy. My opinion and recommendation is to absolutely DO distance running (a nice slow jog for a minimum of 20 minutes, walking is ok if needed) to your pitching routine. The goal is to get your heart rate up and flush out the soreness. Whether that's distance running, biking, elliptical, etc... just get it done.