Hi.. I would like to clarify that the symptoms what you experience is due to neural irritation from the back.. Clinically it can be called as Sciatica... The exact cause could be a Nerve root compression, compromised due to disc herniation or by any reduced lumen through with the nerve root exit in the vertebra we call it as stenosis.. The factors which reproduces the pain pattern as in case bending forward or arching backward .. prolonged siting..etc gives a clinical clue to procedd with further investigation so that suitable treatment protocol be made as per your severity and irritability.. There are various reasons that could lead to sciatica.. Poor posture.. Bad muscle balance like weakness in one side with tightness in the opposite side..less stability..Previous injuries..sometimes even a simple muscle stiffness can lead to such symptoms The treatment depends on the source of symptoms.. I would recommend frequent icing and rest to reduce the pain.. You can have a lumbar support to reduced the load in the irritable structure.. meet a orthopaedic surgeon at the earliest to find out the source of symptoms Hope this is helpful for you.. kindly revert back in case you need further clarification