I am in my late fifties and am in reasonable health. I do aerobic exercises and enjoy quite strenuous walking holidays with no discomfort. However, over the past year or two I have noticed that I am often woken in the night by nagging pains in my hips (I tend to lie on my side). The pain disappears within a minute or two of getting up and moving around. As our mattress is quite old, we decided to invest in a new bed, but although we advised the salesman of my problem before we chose it, the bed we have bought is, if anything, causing more problems than the old one. What can I do?

Dr Fred Kavalier answers your health question:

If you can walk strenuously without any pain in your hips, the problem is very unlikely to be arthritis of the hip joints. Two clues to a possible cause are the facts that you lie on your side in bed, and that the pain seems worse with your new mattress. The bony point at the upper end of the thigh bone (you can feel it if you press on the upper, outer surface of the thigh) is called the greater trochanter. The surface of this bone is covered with a membrane called a bursa. If the bursa gets sore and inflamed, the condition is called greater trochanteric bursitis.When you lie on your side in bed, you put pressure on the greater trochanter. Your new mattress is probably firmer than your old one, and this may increase the pressure. The same type of problem can occur over the tip of the elbow (olecranon bursitis) and the knee ("housemaid's knee"). First of all, you need a proper diagnosis, either from your GP or an orthopaedic specialist. If the problem isbursitis, a local steroid injection may be the solution.

Please mail your questions for Dr Fred to health@independent.co.uk. He regrets that he is unable to respond personally to questions.