I would say the pain issue won't arise if you are moving and getting that adrenaline up. You will know you're hit though. The only times it hurts (for me) are when I get overshot and later that night after playing. There are a few select spots that also always hurt when hit. For me, they are the back of the hand and top of the dome. So I dress accordingly to mitigate the pain if hit there.
I usually run an old tshirt for headgear, doubles as a headband for keeping sweat out of my face and cushions the hits. I was lit up saturday and didn't feel any of the head hits.
PPE is your friend.