@fBoyle-- I received physical therapy for hip flexor pain and it was definitely helpful. I was in a situation where I was afraid to exercise and stretch on my own because I was afraid of causing more injury. But exercising and stretching with the supervision and direction of a physical therapist is very different. I knew that I would not be injuring myself and I'm sure that physical therapy helped speed up my healing.
And physical therapy is not just about healing, it's also about strengthening the body and learning to move correctly to prevent further injury. Speak to your doctor again about physical therapy for your hip flexor pain.