Why is ostearthritis pain worse at night?

I have similar symptoms from nerve pain in my legs.  I wake up uncomfortable and unable to find a position comfortable enough to go back to sleep.  Taking potassium helps a bit.  Standing and shaking down my body for about 5 minutes, sometimes helps. A Pain Mgmt Specialist told me about this.  (Odd looking but it works) Last ditch effort is I take a 325 vicodin and a sleeping pill.  That works 99% of the time.  Sometimes I can't take the Ambien sleeping pill if the episode occurs after say 2 am.  It makes getting up at 7 or 8 almost impossible, though. In those cases I try taking a mild antihistimine like Chlortrymaton (SP?) instead of an ambien.  I have noticed that it is worse after a day that includes a lot of standing and walking.  A friend with similar symptoms swears by this treatment.  He plants his feet up against the wall and pushes his feet into the wall as hard as can, over and over for a few minutes.  That does not work for me.  I have also tried placing a pillow under my knees or between my knees.  That must adjust the irritated parts of the leg nerves enough to calm them down.  Good Luck.  It is very frustrating.  Oh and also, I got a memory foam mattress topper for my mattress.  I am not sure how much it helps with these episodes but it makes actual sleep more comfortable.