This Question Is About My Hip. I Was Standing On

this question is about my hip. I was standing on left leg and taking shoe off on right leg by lifting right leg up and behind me. All of sudden the left hip snapped and dropped down. Ever since it hurts and there is pain when I go upstairs especially. I am active and take yoga three times a week and walk my dog for hour most every day. I have iced and also used heating pad and had rolfing treatment but nothing works.