My upper thigh(pelvic bone?) really hurts?

I dont know what this bone is called but its all the way on my upper left thigh, my roomates think it might be the pelvic bone but i dont know. Anyways, is it possible that I just pulled a muscle or something. It hurts to walk. I havent done anything but go to cl so I dont know why it would hurt out of no where. Yesterday, it did hurt a little but not as much as today. When i spread my legs, it really hurts too. Do you guys have any idea what this bone is called? Sorry for the sucky explanation but I dont know how else to describe it. Has this ever happened to anyone else?