Is rattlesnake bite painful?

Growing up in the. Blue ridge mountain, I knew a man who had been bit on the leg by a rattlesnake. This occurred in the 1950's when people handled snake bites very differently. His brother cut his leg & sucked out venom (please don't do that - now a days we handle it differently). There was no doctor or medical care in our county. He lived but did say it was very painful.
Yes. Such a bite is a double puncture by a large hollow fang containing a toxic brew which seriously hurts and can be dangerous, even lethal. Get help immediately.