Cameron gave an interview to the BBC while he was staying with his family at his stepfather-in-law's property on the island of Jura in Scotland's Inner Hebrides. The Camerons have since moved on to Cornwall for the rest of their vacation.
In the interview, Cameron said he did not go deer stalking this year on Jura, an island with more red deer than people. He said that was not because of objections to hunting but because stalking involves crawling through the heather.
"I find now I'd rather go for a walk, and this year I've got a phenomenally bad back so I really don't think I'll be able to crawl," he said.
Cameron, 48, said he put off getting injections to help with the pain because he believed his back might improve on its own. But he told the BBC he finally gave in Monday.
In the interview with BBC Scotland, Cameron called Jura "a great place to unwind."
"And when you're up a hill on a stiff walk and the rain's coming down and then glorious sunshine with these fantastic views -- there's nowhere better to be," Cameron said.