I found this helped noteably in making me more comfortable and "balanced" on the bike (Limber 11):

What you describe I believe is a combination of mobility issues - muscles that don't turn on, muscles that are gunked up and have trouble activating, muscles that are overly tight, bad muscle activation patterns...there's a whole list of mobility causes. I've had to deal with a bunch of this stuff because of a non-biking leg injury. There's a things that are relatively easy to do that sometimes provide improvement right away:
1. Do some sort of full body work like yoga or light aerobic exercise that moves you around in all direction. Sometimes with some movement and bloodflow things will loosen up and turn back on.
2. Go the the gym workout machines and try to hit every one
3. Get down on the ground on all 4's and move your legs in every direction possible - kick it out to the side, rotate it forward, rotate it back. Some of this is covered in limber 11. The idea is to flush some blood/etc through the joint as well as try to kick the body into using lesser-used muscles that move the legs in odd directions that get gummed up and unused over time.

There are things you can do past this but it gets real complicated real fast and the odds of it working well are about the same as the odds of making something worse....I've gone to "experts" (physical therapists) but they are not particularly good at fixing long term medical problems.