I am having severe low back pain for 10 weeks. I have been to doctor, they said that I have to strengthen my muscles and be more physically active, one doctor also said that I have scoliosis while other doctor denied it. So I attend physical therapy and it doesn't seem to help. At first, my pain occurred while sitting or standing but it was fine when I walked and lied on my side with pillow between my knees. Now it hurts even more and spreads to hips, it is burning pain, I have a feeling like my back is inflamed, but it doesn't hurt when I touch it. Now even injections don't help me, it hurts so much. Also, I am not stiff at all. I don't know weather that matters but my both achilles tendons hurt a little, and my ankles and knees. I also have mild flat feet and wear orthotcis but I have never felt pain or problems because of my flat feet. My grandfather has ankylosing spondylitis so I thought that maybe I have it as well but I am not stiffed. Could you tell where could be my problem? I am 19 years old, weigh 65 kg and have 170 cm.