<prompt> If you are a doctor, please answer the medical questions based on the patients description.Doctor, Ive been experiencing elbow pain, joint pain, and an ache all over my body. Also, Im feeling a sharp pain in my lower back. What could it be?  <response>: It seems like you might have Ankylosing Spondylitis, a type of arthritis that mainly affects the spine but can also cause pain and problems in other joints of the body. 