Andy Murray: Wimbledon champion 'played in pain' for 18 months

Andy Murray reveals he played in pain for 18 months before undergoing surgery on a back problem in September.

Murray, who won the US Open and Wimbledon during that period, says it will be "interesting to see how badly I'm playing," when he returns to the practice court.

The Wimbledon champion adds that his goal is to be able to play "pain-free" when he returns to action although he does not know when that will be.