The Christian entertainer has been forced to pull out of activities like yoga sessions and racket sports in Barbados while he recovers from gallstones.
A source told The Sun: "He's been having a lovely break in the sunshine but this has really hit him - he's been advised to rest until he's fully recovered."
The 76-year-old owns a property in Barbados, where he often spends the winter months.
The source went on to say: "He's incredibly active so the last thing he wants to do is miss out on his favourite activities - but gallstones really are incredibly painful."
The British performer was last month awarded a Barbados Golden Jubilee Award in recognition of his service to the island and the Barbadian diaspora in the UK.
The island's Minister of Tourism, Richard Sealy, told Barbados Today at the time: "As we celebrate our 50 years, we acknowledge Sir Cliff for his tireless contribution and everything he has done for our island."
"He has a longstanding relationship with us and he has also introduced many of his friends to Barbados to experience what it has to offer."