Pain in the back of the leg while running may be sciatic nerve irritation (sciatica), and not hamstring tightness. Nerves need to be mobilized differently.
Leg Pain: When to Worry
Do you experience pressure in your calves when running?
Osteoarthritis: Therapeutic Exercise May Be What The DPT Ordered
Why Do I Have Low Back Pain while Running? The 4 Most Common Causes and How to Fix Them - Competitive Edge
What is the effect of downhill running on neuromuscular fatigue?
Compression for Tired and Sore Legs
Running – Diversified Integrated Sports Clinic
Common Causes for Your Back-of-Knee Pain
Sharp Shooting Pain in Leg That Comes and Goes: Causes and Treatment
Running Biomechanics