Or while trying to sleep....

It has just started in the last week or so, I'll wake up during the night with really sore legs/bum on the side I have been sleeping on. I do roll over to the other side but generally have trouble getting back to sleep because the other side is aching, and it doesn't take long for the new side I'm sleeping on to get sore. Got out of bed this morning at 6 because both sides were aching and I couldn't sleep, plus I didn't have a third side to roll onto!

Have done a bit of googling and it sounds fairly normal, what can I do to help stop them from aching?? I do nothing during the day that would be abnormal for me (e.g. like more exercise than usual), so I don't think it is anything that I'm doing, and I don't want to have to take panadol for it as I would probably be taking them nearly every night! I've heard that sleeping with a pillow between your legs is supposed to help..just have to find a spare pillow...