Flexibility?

Riddle me this…  Is it possible, that no matter how much I stretch, I will never have anything more than average (at best) flexibility?  One would think, with the Muay Thai, BJJ, and years of skiing, that I would have some  sort of bendy and stretchyness to me.  But alas, I am as flexible as a piece of solid steel.  I can’t kick anyone in the head that’s any taller than me.  I can’t even attempt anything that resembles a rubber guard.  When I launch over a gap there’s no way I can do a “Truck Driver” (google it).

Could it be that I’m doing the wrong stretches?  Believe me, I’ve asked myself that time and time again.  I have googled stretching routines until the cows came home.  But it just seems that nothing works.

People have told me that if I want to be really flexible, I have stretch very deeply and hold those positions to the point of pain.  Tried it… Nada…  I am going to try some yoga see if that gets me get bendy.  I just downloaded an app on my iPhone/iPad, so hopefully it will be worth it.  I wonder if it will just be one more thing I check off the list as “failed”?