hey I feel you on the back pain. It will take a while until you feel back at 100% again. Google back stretches, because it's hard to explain some of them. Some easy ones are laying on your back and pulling your knees to your chest, child's pose in yoga, or laying on your back and trying to put your knee to the opposite shoulder (keep your arms out and shoulders on the ground). Strengthening your core is key. Again, Google can help you find good exercises, but some recommendations are planks, supermans, and good mornings (stand with a light bar and slowly try to touch your toes and keep your back completely flat and then stand back up). Also make sure that you use good posture throughout the day.
Hope that helps you out a bit.
just a note:
**I am not a doctor. If you are injured, go to a doctor. I'm just a college student with a history of back problems.**