Many times in runners we see a lot of stiffness in the quads and lack of extension at the hip. Running is great exercise, but it isn’t a complete training practice. On top of that, if your work or day to day has you doing a fair amount of sitting, the battle is a bit uphill. You don’t have to go all out into a full couch stretch to start, find a position you can manage and start. Look at smashing the quads a little before you start the stretch and make sure you add some split stance/lunge work to your training.