My left quadricep gives me the same sort of issues. The solution: I lift weights religiously.
It's gotten me twice now: Once during outdoor track my junior year of HS and once during last cross season. I ran very well in the first race, took 2nd to a guy who would go on to run 24 low. After that, I couldn't walk.
It probably got me due to my own negligence. Yet, I have resolved to not let it happen again and hopefully it never will as long as I am pro-active.
Indoor and outdoor track roll around and I pr'ed in everything from 800 to 10,000 (1:58, ok that kind of sucks, to 30:31)
The things I do with my leg are:
3 sets of 15 reps each using ONE LEG at a time and NEVER more weight with one leg than with the other.
Mondays & Saturdays:
Leg Extensions
Leg Curls
Leg Press
Abductor, Adductor (Have to use both legs at once for this)
Calve raises (Facing forward with one leg, toes point out, toes pointed in, both legs x 15 each)
Thursdays I do a simple leg circuit sans weight.
Step ups onto a chair or other high object
Squats
Lunges (With a 20 pound bar to add some extra)
Calve Raises
Another good thing to do is to stregthen your hip flexors. The best way I've found to do this is to hold your leg at a 90 degree angle and attach some ankle weights once your ready to add weight. You could progress by doing 3 x 30 seconds at first, then 3 x 45, then eventually 3 x 1 minute.