Hey, I am an 18 year old female. The only health problems I have ever had would be Chronic Sinusitis, Acid Reflux, and a deformed patella in my left leg (knee). Nothing serious. But for the past 3 almost 4 months i have had this weird pain in my left hip. It hurts to stretch, and the weird part is, when I am sitting straight up and I look down (meaning in, moving my head down) the hip pain will start. It doesn't last, it just does it and it's over. Same for when I stretch as i already said. Could this be Osteosarcoma? or would my symptoms be worse by now? Please help me.