Re: Why can't i get stonger!
You might try Crossfit Football or just focus on your strength for 3 months doing a pure strength program and cutting back on the CrossFit workouts. Test yourself after 3 months of doing a strength program and see if you aren't better at the standard Crossfit benchmarks.
I like Bill Starr's off-season 5x5 program because it's a strength based program with an eye towards how it will translate to your athletic performance once the season starts. Pick up a copy of The Strongest Shall Survive for all of the gritty details. In addition to lifting heavy, you might try drinking a gallon of milk a day in addition to your normal eating. 170 seems light to me for an adult male of your height. Adding more beef to your frame will help your lifts go up.