ETA Just saw a science report on my NBC Nightly News podcast (their 10/29 show) indicating that as people get older the brain loses its ability to shut out distractions, making it harder to concentrate on a single task while ignoring others. They mentioned how many college kids can study & recall info in a noisy coffee shop or with a TV blaring in the same room, brains lose that filtering ability as we age.
That sounds like me, all right. I've always had trouble distinguishing sounds, following one conversation in a crowd at a party or listening to a podcast against city noises and bus passengers yakking back & forth. The report mentioned using brain training games to improve focus over time, and in some cases medication can help. Of the two I'd rather go with the games, but they'd probably just provide more distractions.