Sudden intense lower back pain started two nights ago. no trauma to area, worse when sitting. ?

Herniated disc,cyst?: THere are a few diagnoses to consider one of which is a herniated disc.Often the discs in our back wear out suddenly & if they bulge,protrude or herniate,they may contact or irritate a nerve causing pain.Often sitting increases the pressure & pain.However,other organs can refer pain to the back including the kidneys,muscle spasm,some abdominal & gyn structures ie ovarian cyst.See your PCP for eval