"Then one day, while doing surya namaskar, I felt a pain ripping through my spine and fell down, unable to move. I consulted an M.D , and he immediately asked me if I had been doing surya namaskar."

This is important. Yoga is very powerful and I think everyone should incorporate yoga movements into their fitness regime.

However, typical yoga classes and even established yoga movement series (like the Ashtonga primary series) are heavily weighted towards forward folding/bending which is the last thing you want to do with a weak/injured back.

This doesn't mean you shouldn't do yoga - it means that you should understand the physiology of a bulging/blow disc and build up your strength (perhaps with other yoga exercises/poses) to the point that you are strong enough to do that forward folding ... and even then maintain caution and moderation.

With a fully rehabbed/asymptomatic L4/L5 I am doing heavy freeweight squats and deadlifts and even inverting during BJJ - but I would still be cautious and even modify portions of a typical yoga class ...