I was recently diagnosed with ankylosing spondylitis. I am a healthy 32 yo female and am very physically active/fit. For 3 days I have had severe left shoulder pain, so painful it is extremely painful to change clothes or even bring my phone to my ear. It's one-sided pain. Could this be caused by AS? Or is it more likely it's a pinched nerve? I had no accident/heavy lifting/etc that would've caused this recently. Thanks for your help.