A couple of yoga moves for your back, the cat and the cobra.
Not sure how best to describe, I will try but type them into google and you should come up with something better!
Cobra is lying on your front hand palm down by shoulders forehead on floor. slowly lift up head the neck and back, think about lifting each vertabra at a time following each other (think snake-like!) go as far as is comfortable, look upwards. Hold for a few deep breaths and slowly lower yourself back down. Repeat a few times.
Cat. Get onto your hands and knees. First arch you back up into a rounded hump, look towards you thighs/knees. Then move through to a hollow backed stretch belly dropping towards the floor, head back, look at the ceiling. Take it slow, you should be like a cat luxouriously stretching! Take big deep breaths throughout.
There will be more but thats the ones that spring to mind.
Hope this helps.