Outside of hips?
I would get a tennis ball or golf ball and use that to put pressure on the area that is painful. It should release the tight muscles. Put the ball on the floor, lay on top of it and try to relax the area you're working on fully. Find the spots that are most painful and put the pressure there. You should feel yourself sink into the ball when the release happens.
Fair warning - this WILL hurt, probably a lot. But it should also fix the problem.
Foam rolling your legs is a good move too - it'll prevent this kind of thing.