hi there, a low back pain
in itself if not significant and does not point to any particylar condition but with a raised ESR
could indicate some disease process going on inthe body. One of the most common casue in India could be Tuberculosis
and for that you need to get an MRI
done which will help to rule out bone TB. Or they could also send your CSF for TB PCR which will slo help in ruling out this condition. If these are negative then you may vist a physiotherapist and get exercise done for strengthening of the back muscle which tends to take the toll when you sit with bad posture for a long time expecially if you are into sedentry work like in front of the computer or any such work. Take care.