Dear Madam,
I am happy to see that you have given adequate information about your self and have formatted the question very well, it helps me to understand your problem better. As you say you suspect
kidney problem, well yes it could be as renal stones are fairly common among IT professionals , the reason being woking in Ac environment all the time, that makes you loose lot of water from your skin and also the water intake is less, high stress levels, sitting for long hours all this add to problem. In your case I feel the pain is more due to sitting for long hours and working. When you sit for long hours and work on systems, it spoils your posture and puts excessive strain on the muscle of back, particularly the one which support the spine, this too is one reason for the kind of symptoms your are facing.
Next Steps
I suggest you must increase intake of water, do yoga and aerobic exercise everyday, please get a UGS scan of your abdomen done to rule
kidney stone. Please get your blood checked for Vit D3, in case it is low please see a doctor and take medicines to correct the deficiency.
Health Tips
Do not sit for more than one hour at a stretch, every one hour get up from your chair, walk for five minutes, drink at least 250 ml of water and start working again, do this every hour. Yoga and aerobic exercise is a must. Completely avoid junk food, particularly fizzy drinks. I wish you a happy and healthy life.