How To Reduce Lower Abdominal And Back Pain During Pregnancy?

Hi iam Kiran.... i am pregnant (5 months) suffering with back side pain and lower abdomen pain .... all reports are normal.... doctor advised me for bed rest and prescribe me mefkind - spas as SOS after meal ..... also this is my second pregnancy .... first delivery was through operation... please suggest is mefkind spas is helpful and the reason of pain as nothing is showin in sonography and all other reports