It might me muscle sprain as per your complaints. Get Xray Lumber spine AP/LAT just to be sure.

This treatment is being on bases of the information provided.  However I would like to examine & investigate you  in detail. -Control  Hypertension, Diabetes or  metabolic disorder, if there is any.  -Any way it may be tried, --. Dolokind Plus (Mankind) [Aceclofenac100 mg +Paracetamol 350 mg] 1 tab. OD & SOS. X 5 days. --. Caldikind plus  (Mankind) 1 tab OD x 10 days. -(You may need help of your local doctor to get these medicines.) --. Fomentation with warm water. Let the part not be exposed to cold. --. Sleep on a hard bed with soft bedding. --. Keep no pillow under the head. --. Avoid painful acts & activities. -- .Do mild exercises for the back. --.(Take help of physiotherapist or you can visit my you tube channel Dr NC Gupta.)   & see  me and my yoga; & yoga simplified. Kindly subscribe to the channel to get notifications for further new information of your interest.  --Do not ignore, let it not become beginning of a major problem. --Do ask for a detailed treatment plan. Kindly make sure, there is no allergy to any of these medicines. --For emergency treatment visit nearest hospital. --Wish you a quick recovery & good health. --I hope, I have solved your problem to your satisfaction.   Dr N C Gupta MS (ortho) DMC 3624  

Could be acute lumbar sprain Take adequate rest, muscle relaxant (tab.myospaz) Hot fomentation

Rest Hot fomentation No massage or any physiotherapy till pain stops Avoid strenuous activities, prolonged sitting and standing If severe pain, radiating pain, tingling numbness in lower limb, weakness in lower limb, bowel and bladder complaints visit nearest Orthopaedician

Muscle pain more likely Rest, medicine, hot water bag massage