Tight hamstrings may be a symptom of anterior pelvic tilt.
The hamstrings are trying provide stability to the pelvis.
Have you done a search of the archive for hip extension or hip flexors?
There are several which address these.
A couple to start with
How to Fix a Pelvic Fault or Tweak

Wednesday, February 15th, 2017 – Hip Flexors

Episode 249: Improving Hip Extension (And Internal Rotation) for Running