You most probably got lumbosacral strain. Take muscle relaxant meanwhile visit a Ortho doctor around you. Warm fomentation.

Avoid forward bending use hard bed Tab accept th bd morning and evening Tab pantocid dsr before breakfast Tab pre m night Tab calgel ds afternoon Collamax sachet 1 per day with a glass of water Tab mocal d3 once per week ice water fomentation with dynapar qps spray Back extension exercise High protein diet Dr Chopra’s Spine Joint Solutions India http://drchoprasspjsi.co.in/