Lower back ache when I wake up in the morning

[Paddingtonthebear]

My lower back really aches when I wake up in bed every morning. It wears off within about 10 mins of being out of bed. I've had this on and off for a few years in different beds, we have a new mattress now and the actual quality of sleep is much better. So I don't think it's the new mattress. I mainly sleep on my side. I think it's the position I sleep in. I've tried to sleep with a pillow between my knees but it always ends up on the floor. Is there anything I can do, or is this sign of getting old

[lavendersun]

You need to stretch, I stretch every morning while the kettle is boiling.

Pilates yoga or simple stretches, Google stretches for lower back there will be something on you tube.