I would think that it was the needle at the tip of the catheter that nicked your lung, as that is the only portion of the device that would get that close. I have had zero problems with my port, and the surgeon who implanted it was 83 years old at the time. I thought he was ready for retirement until the RN told me that he had retired twice before! He is one of the pioneers in ports and catheters, though. I was also blessed in that I had no problems with the Hickman that was placed on the other side of my chest.
shhwee, surgeons have also nicked my dura twice in other surgeries, causing CSF leaks and overnights in the hospital as well. One on my brain and the other on my lumbar spine. Kinda has a ring to it, though: "That surgeon really nicked my dura!"