
OK, so it took me a bit more than 12 weeks, but I completed all 12 weeks of the p90x program. I didn't do so well on the diet part of it, but I've definately added some muscle mass and feel like I've made some improvement on my PE. I'm finally just starting to get a hint of definition between my pecs, which I think is going to be most important in the appearance of my chest, but more important than appearance is how I feel about my overall health.
The more I exercise, the more I realize how important balance is, the balance between your chest and back, the balance between biceps and triceps, the balance between quads and hamstrings, between upper and lower body, and the balance between work and relaxation. And the more I realize the importance of balance, the more I realize how much my pectus excavatum has thrown off my balance.

PE is caused by an over growth of cartilage where the ribs meet the sternum, which causes the sternum to grow inward, pulling the center of the chest toward the spine, causing the shoulders to curl forward which tightens the muscles of the back and throws the neck forward. The hips have to adjust to attempt to balance the upper body on top of it, which can cause problems all the way down to the feet.

I've also slowly come to realize what should have been blatantly obvious from the beginning: that muscle tone and mass is simply a reflection of your physical abilities, and that to get the results I want, I need to work hard at becoming more capable. Cage fighters look the way they do because they have the ability to beat down most men. Free runners look like superheroes because they can perform superhuman feats. I look different now than I did a year ago because I have the ability to do many things that I couldn't do before, but it's not enough. I will continue to work hard, not only to improve my PE, but also to improve my strength, my abilities, and my balance.
I'm sure I would have made faster progress if I had the drive I do now when I was still growing, but I didn't. It takes 8 years for your body to replace all the cells in your skeleton, and if it takes that long, so be it, but I will not have PE forever.