Training to failure has its place. That place just isnt in every workout, every set. IMO its best to change your intensity throughout your sets and that does occassionally include failure. Just not every workout, every set.
Current: 34 yrs. old 5'10.5'' 192 lbs.
Goals: 195 lbs. 12% bf by dec.09'
Long term goal: 225 lbs. 10-12% bf
Best Lifts bench:355 11/10/08 Deadlift:475 5/5/08
Squat:395 5/6/08.......Total:1225 RAW
Goals: 1275 total by Dec 09'
Long term goal: 1500 RAW
I think you are maybe showing the signs of overtraining mate. Hitting your chest wtice a week and going to failure as much as you are.
I had a similar problem once and cut back.
By all means go to failure on some sets.. even beyond at times but not all the time.
Train,train hard.Eat,eat lots and sleep even more.