My iPhone has somehow locked so the screen will not rotate?

Phone screen stays oriented up and down, when rotated 90 degrees it does not orient side to side. There's also a little symbol up top with a lock with a circular arrow around it. I think it is locked and I can't figure out how to unlock it. Can anyone help?

I didn't read your question, and The Bruins Suck Balls.

Yes you have portrait orientation lock turned on, this is useful if you are lying on your side in bed and you want to read without the screen turning.
To turn it off, double click the home button, swipe to the left, and click the button as you described, on the far left.
Hope I helped,
Alex