Kara I agree with PAlady here and I know I have sciatica and it effects my hip some times more then anywhere else,even when the pain is more down my leg it seems to originate in my hip before moving on.
My back problems are also in the same region as yours so it may be just that happening with you as well.
I hate it when it flares up as it is impossible almost to get any relief.
I also have severe knee problems and this is where most of my problems are and I have hip pain from those times before my knee replacement when I was favoring my knee or limping and put undue pressure and work on my hip.
If it doesnt let up soon you need to get in and have a MRI just to make sure there is nothing going on that needs attention.
Good luck to you and hope you see some relief soon.