Ahh, if my massage table could talk...it would tell the tale of runners it's seen, runners with "mystery" hip, leg, knee, or ankle pain, always on the left. My table knows the secret to this mystery, deduced over time. "It's because you run on the road", it whispers, roads that are slightly off-camber to the left, allowing for water drainage.
Of course, your response will be "Well, where am I supposed to run?". No worries, a guy/girl's gotta run, and cobbling together enough mileage on flat sidewalks is a pipe dream. My table would counter, "Do what you love!! Then come take a rest on my heated, cozy surface, and let my therapist address the tightness in your left side."
"My massage therapist says pain in the hip is often a trigger point in the gluteus medius or minimus, or mabe a tight TFL/ITband that isn't responding to foam rolling. Most runners know their ITband contributes to leg pain, but a chronically tight ITB can aggravate the peroneus muscle (which runs from the outside of the knee to the outside ankle), especially if you're running on off-camber roads. That tight peroneus muscle, along with a tight tibialis posterior/anterior, can cause pronation or supination in the foot. Check the wear pattern on your shoes - are you wearing out one side predominantly?"
Do what you love. Just remember to take care of yourself so you can keep doing it. Book a regular therapeutic massage, with a table who knows runners and feels your pain. You can meet my table occasionally at Fleet Feet sports events, and always at Myocare Neuromuscular Pain Relief Clinic. Come say hi; my table loves company. ;-)