Your "lumbar spine," or low back, is made up of five bones that are placed on top of each other and separated by a shock-absorbing disc. The muscles and ligaments that cover your low back provide a lot of support. "Sprains" and "strains" are a direct result of these tissues being stretched too hard or too far, much in the same way that a rope frays when it is stretched beyond its normal capacity.
A "sprain" refers to damage to the thick, robust ligaments that support bones, whereas a "strain" occurs when the muscles or tendons that move your trunk are partially ripped.
Bed rest is not in your best interest. You should only allow yourself to return to normal activities as your symptoms allow.
For a brief length of time, using a lumbar support belt can assist relieve your discomfort. Sitting increases the risk of sprains or sprains caused by abrupt movements in the back. It may be wise to take "micro-breaks" from workstations for 10 seconds every 20 minutes. Following acute injuries, you can apply ice for 15-20 minutes each hour. Heat may also be helpful after several days or for more chronic origins of pain. Be sure to inform your doctor of your exact situation and to ask for specific ice/heat recommendations. Sports creams have provided partial alleviation for some people.