Night-time knee pain

[PleaseReferToMeAsBritneySpears]

For about a week now my left knee hurts all night. Twice I've taken painkillers at bedtime and it's been slightly better but it keeps waking me up and I'm getting really tired now. The pain is quite severe and constant. The weird thing is it doesn't hurt during the day at all. Absolutely no bother.
Why does it hurt at night and not during the day?

Could it be arthritis? When you're on the move during the day you keep the joint warmed up and lubricated.

Try a physio, mine helped a lot.

Hope you can get it sorted, losing sleep is miserable.

Hmm maybe. I'll google arthritis. Thank you.

Did you get to the bottom of this? I'm feeling the same. REALLY painful at night but NOTHING in the day. So strange.

I’ve had this, it feels so weird. Fortunately mine cleared up after a week or so. I put ice on it during the night which seemed to help a bit.

The pain is because at night your muscles relax. What you need to find out is why they are having to do so much work during the day. Is it your knee or your hip?