When her left shoulder began to ache shortly before she turned 50, my sister Carol Wilson ignored the pain and put it down to a poor-quality mattress. She hoped the situation would resolve when she moved house in the UK – and got a new bed. The pain continued. “I kept hoping it would get better,” she says. “But it didn’t.” Her doctor diagnosed a frozen shoulder and alluded to it being something that occurred in “women of a certain age”. He prescribed physiotherapy, which didn’t help her much,...