Thanks for posting on HealthcareMagic.
After reading your symptoms i feel that you need to incorporate certain things in your daily schedule:
1. spinal extension exercises, which your doctor had suggested earlier. You must start with them again on a regular basis.
2. local analgesic
ointment: If the pain is more, apllication of any local analgesic ointment will relieve/subdue the pain.
3. Lie on hard bed while sleeping
4. Physiotherapy: Getting few sessions of physiotherapy will definitely make you feel much better and once you exercise as well the problem should resolve.
5. Take walking breaks after every 2 hours while working, stretch and bend if possible to relieve the tension in the lower back.
If, after following above mentioned routine, the pain still persists then you must get an Xray spine done and revisit your orthopedic surgeon for clinical examination.
Hope you feel better soon.