What causes back and chest pain in teen?

Answer

Experienced severe back and chest pain that seemed to move in location in response to physical movement. It was extremely painful and hard to breath, but I did not have an irregular or fast heartbeat. It happened about four times in an hour and then went completely away and it's been more than a day, but now I have severe cold symptoms and a low fever. Any idea what it is? I thought pneumonia or bronchitis?
The back and chest problems could be from having heavy backpacks with all your books in them. I have the same problem and I am still suffering from some of those symptoms and I believe it is from carrying heavy backpacks for all those years that we have been in school.