Only your left arm?
Wait till you get older!
Actually the reason it hurts is because each time you cast it is like re-spooling the reel with line!
Re: distance. One day it was blowing good from behind me helping my casting disatace...I pulled out the Arra/Stella/30# PP combo I threw a 4 oz Megabait jig hard just to see how far I could go given everything in my favor. I swear it went into orbit. I couldn't judge how far it went but it was way out there.