Sir I have a back pain at the right side. It is normal pain while driving or sitting on the chair but become high when sitting on floor.

Back pain. Increased pain while sitting on the floor without back support is most likely muscular. It could be the sacroiliac joint as well. Disc herniation can also cause pain while sitting but is usually midline and not to one side. Try using lumbar support or simply a pillow behind the lower back. Change position frequently whenever possible.
Seated low back pain. One sided low back pain coming on in the seated position as described can be from disc injury irritating a nerve root, sacroiliac joint, iliolumbar ligament, etc...Sitting places significant force across discs of the low back & sitting in the position described, maximally loads the joints & ligaments connecting the lumbar spine to the hip. Stay active, stretch, swim, yoga, pt, chiro, injections..