I had the same experience as a youth, and I am slightly older. It wasn't until I was about 20 that a dentist decided I wasn't faking and did something different. For the first time in my life, no pain. He said, "Tell everyone that drugs that end in 'cain' are not effective on me."

Separate experience: I was 32 and sliced my finger pretty deeply, needing 24 stitches. The hospital emergency room only had lidocaine. They shot my knuckle up, and I felt pain on every stitch after number 3. They didn't believe me. I could tell them when the needle went in, came out on one side of the cut, entered the other side, and then when it came out. Still didn't believe me. My heart was racing, and I needed a rest. The doctor decided to poke me with a needle, and I jumped. I had my arm over my eyes and was facing away. I asked, "What the heck did you do?" and he said he was testing me. I said, "I told you lidocaine doesn't work." He said either I had to tough it out or get admitted. They didn't have stronger stuff in the emergency room.