Question: Can shoulder immobility be related to pain in the thoracic spine?

I've had back pain for years throughout my entire spine, and it hurts everyday...constantly. However, a few days ago something happened in my mid-back area (I didn't do anything to cause it) and I could hardly move. It was unbearable; even leaning against the back of the couch hurt. Things like this have happened before, but never quite to this extent. My leg even decided to join in on the fun. When walking, everytime my right leg hit the ground, it shot intense pain right up my back. (The pain was along the right side of my spine as well)

And the next day, my right shoulder was noticeably weaker and sore. Throughout the day my shoulder was just hurting more and becoming more stiff. About halfway through the day I moved my arm around a bit to try and loosen up, and discovered that my arm could not move up past my shoulder when extending it directly out to the side. And trying to move it was excruciating.

Also, I forgot to mention that I am a fifteen-year-old female. Don't know if that's relevant, but if it is, it's there.

Could my shoulder issue be related to my back problem? And if so, how?

Thank you!