Read Baron's reply:
Before I explain the physical dynamics, it's important to remember that your emotional life can affect the condition of your pelvis. Your life's diary is stored in your body. It could be held in one place or in many places—shoulders, lower back, certainly the hips. So your emotional health is the first place to start in successfully
releasing your hips.
Assuming you are doing the necessary emotional work to stay healthy and balanced, let's look at some physical dynamics of your practice. The repetitive impact of running causes compression and tightness in the overall musculoskeletal system and specifically in the pelvic muscle groups. Consider giving up running temporarily and focus on releasing, opening, and creating more space within your body.
Yoga helps your body relax overall, which allows it to blossom and release tension. Try a well-rounded vinyasa-style practice that heats you up. It can help open up your whole structure. Once your body is warmed up, you can focus on more muscle-specific and static postures based on your needs (in your case, the hips).
If it's important to you to continue your cardiovascular work, consider switching to a form of training that has less impact, such as swimming.
Baron Baptiste, author of three best-selling yoga books, has trained Hollywood celebrities, Fortune 500 CEOs, and NFL athletes, as well as tens of thousands of people through his bootcamps, teacher trainings, workshops, and Studios. Baron was born into a lineage of yoga teachers and has been teaching for more than 20 years.