welcome to Health care magic.
1.The pain you are describing looks like
nerve compression, this happens when the disk which suppose to be between two vertebrae, slips / herniated backwards and indeed on the nerve.
2.First you have to get a x-ray
lumbar spine AP/LAT to see gross abnormality and bony pathology.
3.After that get an
MRI scan lumbar spine done, which will gives the condition of disc, nerve , and chord.
4.Once reports are there one can decide weather needs any intervention / operation. Or may just need some exercise on daily basis.
5.So, take an appointment with your GP and get the needful investigations done.
Hope it helps you. Wish you a good health.
Anything to ask ? do not hesitate. Thank you.