Back exercises that i have researched and a doctor at PIMS told me to do the exact same.

http://orthoinfo.aaos.org/topic.cfm?topic=a00302

1.Single Knee to Chest Stretch 
Then both knees

2. Straight Leg Raises 

3. Hamstring Stretch  


PIMS doctor told me to do them 20 times a day, which is crazy. But see which ones work for you, and do them whenever you can.