I have been pierced...the PA wasn't bad, but the penis is highly vascular tissue, so there was more bleeding than, say, piercing an earlobe. Having a nipple pierced hurt quite a bit more.
As for pins, don't do it. They are not sterile, they are too large, and they aren't sharp enough. For needle play, use disposable hypodermic needles, and follow sterile protocols. IF you want to get into needle play, do some serious reading. Don't fuck around with your health.
"We need to make books cool again. If you go home with somebody and they don't have books, don't fuck them."