My BO, in December 2007, involved incisions in the lower groin area, under a general anesthetic. I chose this more radical surgery to avoid scrotal scar tissue in the belief that GRS, should it ever miraculously become a real option, would proceed more easily.
That said, I was on hydrocodone pain killers for the first 3 days and then moved to ibuprofen. Since you'll be getting a simple orchiectomy the recovery period should be a lot shorter than mine. You'll feel as if you got kicked down there for a few days but the discomfort will decrease steadily, as long as there are no complications. Good luck with your surgery!
hugs & smiles
Emelye