Leg Pain, Tight Hamstrings

Everytime I go for walks that last over 15 minutes, I get pain in my right hamstring and calf. The longer I stand upright the more intense the pain gets, and if I sit down the pain goes away in a matter of seconds. My right glute seems to be stretched compared to the left, and if I stretch my adductors and hip-flexors the pain goes away for a few minutes but then returns.

My right hamstring is ridicously tight, but stretching it seems to worsen the pain.
I’ve tried stretching my adductors and hip-flexors almost every day, but it doesn’t cure anything. I don’t have lower-back pain.
I’ve been to a PT, but she just told me to stretch and it doesn’t seem to fix the problem.

My standard answer is go see an ART person. They may find some scar tissue or something that needs to be worked out. ART doesn’t always work for all my problems, but it does always work when my hamstrings are concerned.