I've had a long battle with hamstring tightness and pain (in my case, it is very high right at the attachment to my butt) and over the past few months have seen a lot of improvement using the following routine. It seems that half the runners I know these days are having hamstring problems, and a few of them have also had luck with these exercises; no guarantees that this will work for you but they certainly won't hurt and getting your legs stronger and working on balance is always a good thing.
It may hurt to do these at first, which is why I resisted for a long time, but in the end it is more important to strengthen your hamstrings even if the exercises do aggravate them a bit more in the short term. The key for me was doing exercises that load the muscle eccentrically (when the muscle is also being stretched) as this is the way the ham is used when running.
I don't do all these exercises every day, but try to do at least a few of them each day and more of them on the days I weightlift. The following photos and descriptions will hopefully be enough to get you started. Feel free to comment or email me with any questions about any of the exercises.
1. Walking Lunge. Walk slowly forward while lunging down on each leg. The further you put the forward leg in front you, the more you isolate the hamstring (rather than using your quads). The walking part is key - pick an area where you can take about 10 steps in one direction and then turn around and come back. The whole time you are walking, you should be low to the ground (don't stand up but rather drag yourself forward while maintaining the low position).
2. Romanian One Legged Deadlift. This one is also a great core balance exercise. Balance on one leg and hold a dumbbell in the same hand. Keeping just a slight bend in the knee, bend over letting the dumbbell get close to the ground before raising yourself back up. This works on balance and you'll feel the hamstring working.
3. Leg Curls. Use a machine that allows you to do one leg at a time. Use a light enough weight that enables you to slowly flex your hamstring, bringing the weight to your butt. Slowly lower it down and repeat 8 - 10 times for each leg.
4. Good Mornings (aka Straight Legged Deadlifts). Put a barbell on your back as if you were going to do squats. Keeping your legs straight and your lower back arched, slowly stretch down till your upper body is parallel to the ground. Slowly raise your upper body back up till you are standing straight again. This also hits your lower back so be careful if you have back issues.
5. Eccentric Hamstring exercise. Using a partner or by wedging your feet under something (note; dogs can be effective ballast), and while keeping your body in a straight plane from your knees on up, slowly lower yourself towards the floor. Use your hands to stop your descent. From the down position, you may have to push off to get started, but then use your hamstrings to pull your upper body back to the starting position.
6. Ball Pull. Lie on your back with one leg stretched out on top of the ball. Your butt should be off the ground and your other leg should be up as shown. Slowly pull the ball back and forth (towards your butt). At first, you might struggle with keeping your foot on top of the ball as your core tries to stabalize itself.