It has been 6 weeks since my fusion surgery. On Sunday I rode in the car with my husband. I went to adjust my seat and the seat flew back really quick and it felt like I pulled something. Two days later when I get out of bed, from a laying down position, it feels like something stabs me in the lower back as I get up. What could this be? I talked to the nurse and she said I probably just pulled a muscle, since after surgery the muscles are still weak.