There really isn't any way to punch a hole in your body without there being "some" pain, one way or another. If you see a professional piercer (which I highly recommend) the piercing process itself isn't all that painful. Its very quick and they know what they're doing. Even if the piercing process isn't all that painful, you will still have pain because there's a hole in your flesh. The hole will hurt until it heals. Depending on where you get the piercing, the thickness of the piercing, and what tissues are being pierced, it may take anywhere from a few weeks to a few months to heal completely.
If you do decide to go for it, talk with other people who have piercings. Find out where they had it done and if they were happy with it. Then check out the piercer and talk with them about the piercing, their hygiene practices, and what to expect during the healing process. Call the health department to see if there have been any reports of Hep-C or other diseases associated with that shop.
Yes, this sounds like a lot of work for something that's supposed to be fun and "fashionable". Then again, we're talking about punching a hole in your body and isn't something to be taken lightly, especially considering the possibility of getting a serious disease if the shop doesn't follow strict sterilization/hygiene practices. I have 14 piercings (11 in my ears and 3 elsewhere), and have done this screening process every time I consider going to a new shop. Its better to be cautious about this, rather than rush into it and be sorry later.