Lower back pain. But pain came back.

I've been experiencing lower back pain from past 3 months. Initially I experienced severe pain at times when I sit and bend. But now I experience pain when sit down (with my legs folded or stretched) and bend forward. I'm not able sit down for long with or without support. And i feel the pain when i bend forward and backward(both in sitting and standing position).I had actually started cycling (20 min) and crunches (15-20 min).After a week(approx) of doing these I started experiencing pain,after which I rarely exercised and after a month I completely stopped exercising. I have no clue if the pain is because of wrong exercising. Initially I massaged with Iodex for few days but didn't feel better so I stopped applying and I did not use any pain killers. I had taken gastric tablets for 3 days,felt little better but pain came back.