Weight gain after pregnancy is common and needs serious attention to reduce. It is true to be the cause of Back pain for you. Being a Software professional you are also prone to Computer related injuries and back pain as common symptom, because of poor postural practice. We are attaching the document that would describe in detail as to what measures that you can take to maintain the posture at work. It contains the exercises that could be performed at the work desk. It is prudent to get an X-ray done (AP view and Lateral View) to the corresponding spine to rule out the serious causes if any. If you have Back pain persisting even after a week to 10 days of exercise then it is advisable to meet the Orthopedician and get the appropriate treatment for the same. During the episodes of the pain you can adopt various methods like putting hot bags and hot water fomentation or cold packs at the back( if you prefer). Resting on a flat surface for a few hours. Taking care of your posture is important during the work. Stretch exercises and Regular walking in the morning keep you at bay. You can also take Over the counter pain killers to gain immediate relief.