There may be something to that higher pain tolerance. Years ago I had major jaw surgery where they split and broke both sides of my bottom jaw, brought it forward and then put titanium plates in to hold it together. When I woke up the nurses kept trying to get me to press the pain med button because I just didn't. Take home pain medication was only taken for two days and then forgotten about.
Throughout the whole thing I didn't feel any pain, just a bit uncomfortable. Mum joked that I looked like a squirrel storing nuts.