Always do your best to beat yourself. That may sound cheesey, but there's ALWAYS someone stronger than you. Just keep learning all you can and busting your own PRs, and work your way up.
The deal with the bench isn't just drugs. It's the shirt, better tranining, better attitude, a sky's-the-limit viewpoint... Oh! ...and a bench shirt (yes, I said that twice).
I bench about 250 in my shirt, and I'm a 180 pound female. I'd like to hit 300 by this time next year, but I too have shoulder issues. Not from traning heavy, but from benching "like a bodybuilder" for a year. Really jacked em up. Powerlifting has actually HELPED me. They're still my weak link though. My floor press is, and has always been, 177 pounds. My lockout (top 4-6 inches) is 403 pounds. So, they come together to allow me to move 250, but I know if I can bring my shoulders up, I would see the results I'm looking for. What did you do to your shoulders, exactly?
I really admire your drive...some people think 40 is old.
Again, I would encourage you to open your mind to your own strength potential. I could barely bench the bar without pain 7 months ago.