First of all, don't do ay more physical labor for the next few days! Take motrin (500 mg) every four to six hours until the pain is gone. For the first few hours ice your back. 20 min on 20-30 mins off. Then switch to warm heat. Try to remain in a prone position but add gentle movement as tolerated. Carefully loosen your back by slowly bringing one bent knee toward your chest then the other. Start slow, adding inches at a time. Tomorrow try adding add both knees. Remember slow and gentle. Watching TV on the sofa should also be considered!