I've noticed (a personal preference) that icing my arm the day after helps the most-sometimes when I ice after, stiffness still arises. Usually the day I pitch I don't feel pain. The day after I pitch the muscles that slow down the arm (mainly located in my back/shoulder blade region) are very stiff. Icing one time for 20min, next day they are perfect. I run after starts, and pretty much every day for HS, but this worked during summer too when I wasn't running as consistently. Once again, personal preference. If one is worried about lactic acid, then do tubing or running and ice. Swelling is the main thing (I've been told, and once again it's a personal condition) that causes ME stiffness-not pain. The ice helps with that. I'd say find a balance of icing, running, and tube/shoulder exercises to do consistently on a schedule around each start/outing.