When you bench do you use a safety rack, Smith machine, power rack, etc? Or do you just lift from the rack holder's over your head with out a spotter? Can make a difference because some guy's haven't developed the confidence to use more weight without some sort of insurance of safety. (Let me add that by any account, benching alone with just a bench rack is a very, very bad idea) Even with good equipment or spotter a few will have a sence of failure when trying to add weight to the bar. And a few guy's I've met had a dread of lifting a weight overhead, like in the BB press (this can happen in the squat also, a heavy weight on the neck/shoulders some how brings fear). In my view, lifting is just as much a mental process as it is a physical one, maybe more so.
I'm not suggesting the above may be your problem, just an added thought. If your young enought and some what new to training than the weight's/rep's you use should be going up each workout, at a steady pace. If all things being equal and you have the confidence and saftey equipment/spotter than do one warm-up set of 10-12 reps with a light bar. For the working set's drop the rep's between 6-9 for three set's of benches with a mediun hand spacing and two set's with a close grip, keeping the elbows close to the side. Don't add any other chest exercise for a while, not until you get use to regular BP'ing workouts. The weight on the bar should advance steadly from each workout to the next. Try twice a week workouts. If you feel your progress is not what you expect than only have one bench workout every 5 to 7 days.
I've read white paper's where men and women have gained strength through controled weight training well into their 80's or more. So there's hope for all of us. Good luck.