Re stretching tips:
* Always stretch when you are WARM (i.e. AFTER training or after a hot shower pre-bed) - your muscles, tendons, and ligaments are more pliable (and stretching is also a form of "recovery"). Do not ever stretch cold (especially re static stretching), because this increases your risk of injury.
* When stretching, go to the point just before pain and hold.
* Hold stretches for 20-30 seconds each.
* If stretching post-training, focus on stretching the muscles worked during that session.
There are also different kind of stretching (i.e. static and dynamic, assisted and unassisted), and you should choose the one relevant to you. You could always try a yoga class as well, and see how that goes.
Stretching will definitely help re flexibility. I always recommend stretching for 20-30 minutes a day (and have done this myself since I was 14 years old).
Hopefully this helps a bit