In reply to Pesda potato:
They are quite simple and a youtube video is much better than my descriptions. These aren't going to fix your problem (rest probably will, and ice) but you should get into the habit of stretching after runs or on rest days to maintain flexibility.
Pull foot to bum for quads. (I do it lieing on my side with my front knee bent at 90 degrees for a deeper stretch)
Hamstrings. Put stretching leg forward, keep it straight. Bend back leg and KEEP BACK STRAIGHT as you bend forward. You don't need a step.
Glutes, hold onto a post or door frame and lean back. Put one leg over the knee of the other and 'sit' as you go backwards.