**Moved the thread to put it in the appropriate forum.**
Looks like you have to work on your flexibility. Make sure that you encorporate a lot of stretching (especially dynamic stretching) to your work outs. Kick stretches will help with the range of movement, that all comes with a bit of repetition and time. I don't subscribe to the "super-flexibility" stretch exercises, and I don't know how being able to pull the splits while being suspended between 2 chairs helps you fight. Sure, it's great for book covers, but successfully winning fights can get you there just as quick.
But since you noted that you have a hard time kicking above your mid-section, you might take that as an opportunity to work on your form. As it is, the greatest amount of power that can be generated in a kick is generally from the mid-section down, and high kicks tend to be extremely high-risk in actual fights.
Then again, so are flying armbars. But knowing that you can pull it off is always a great thing. In any case, this book right here
is a great start for training kicks. It is written by grandmaster Hee Il Cho, who has been studying and practicing Tae Kwan Do for the majority of his life. Sure, TKD is popular in the MMA ring, but you can't deny that TKD practitioners know how to throw kicks. I have the book myself, and it not only breaks down the kinesthetics of each individual kick, but it also has drilling routines, stretching routines and strength exercises for each kick.