Lower back pain can be caused by a number of conditions, some serious, but if it occurs suddenly or after activity, then it could be a muscle strain. Strains are caused by activity and impact, according to Spine Health.* Heavy lifting. Lifting improperly can cause back and muscle strains.* Sudden impact. Jarring motions from sports, a fall or a car accident.* Repetitive … [Read more...] about How to treat sudden lower back pain