This lump is causing pressure on intervertebral disc joint and emerging nerve which causes numbness and shooting pain that radiates to leg. Lump has to be clinically checked whether it s cyst, abscess or bulging of osteophytes like cartilagenous thing or what. It has to be removed surgically. However some Ayurvedic Medicines may help reduce it like Kanchnar guggul but extent of relief can not be ensured. For the time being antiinflammatory and analgesics 1 sis may be taken but do not make it a habit please. If some some intervertebral gap is reduced and causing friction of bones, that may also cause lump. This all has to be managed by band support or traction at ortho centre. Only med will not give sustained relief if possible situations as mentioned above are present. Hope it helps.