I'm almost as old as you, but I can play more golf now than ever before, without pain.
I played 124 holes of golf Saturday and Sunday.
Not just short courses either.
2 rounds at White River (blue tees) then 18 more at Lakewood on Saturday.
2 rounds at Twin Rivers, then 34 holes at Lake Stevens on Sunday. I would have played today, it was so nice out, but I had to work.
One round used to destroy my arm years ago, then I would not be able to play for a couple of days, now I can play till my legs give out.
The secret is the changeup. I throw almost 50/50 forehand/backhand drives now, so my arm doesnt get destroyed by all the backhand stress, this makes a huge difference.
Playing well helps too, if you only have to throw two shots per hole, instead of four, its half as tiring, plus its amazing how tossing birdies blocks the pain from sore muscles.