I have also changed up my grips, wider cause i heard that over a period of time it can result in greater strenght.
You can generate more force off your chest, not so much towards lockout. Powerlifters sometimes use wide grip only because they have to pause on their chest before pressing.
My pinkey's stay on the rings, and I can press 405 lbs.. About 20 lbs less if I widen my grip. So it depends.
For a big bench, you need to continue hammering away at your triceps. Period. More chest specific exercises won't do a thing if your triceps are weak.
As everyone else has said, where's your "sticking point"? In other words, where does the bar stop moving? If you're getting stapled on your chest, then you need to incorperate some pause presses, OHP's, closegrip bench, ect. If it's a few inches off your chest, do some 2-3 board presses, pin presses (I don't like them), floor presses, ect.
Or you could do something like changing the sets/reps scheme. If you've been doing 5x5 for so long, try 5x3, 3x3, 6x1, ect.