Since when is the pain? Do you have any urinary problems? Any significant past medical or surgical history? Any injury to back? Does the pain occurs on sitting and standing also or it subsides completely? Were any investigations or imaging done?
With your existing history of spine problems, I feel this can be bone spur which pinch on the nerve when you lie down. A secondary muscle spasm do occur with the problem which cause pain only in specific positions, when this muscle or muscle fibers come into the play. With the problem persisting for almost two weeks and pain intensity quite high, ideally, you should contact an orthopedist or a rehab doctor (MD in physical medicine and rehabilitation) for a physical evaluation. Taking Motrin, applying hot packs, local analgesic ointment (patch or spray), and physical therapy in the form of simple stretching should help you, meanwhile.
Please feel free for your follow up questions.
Pain which only occur with specific body positions or postures are unlikely to be related to the visceral organs (liver and kidney).