Protruding disc l4-5 l5-s1 touching both s1 roots, indents thecal sac, neural narrowing. is this a serious problem? whats the estimated recovery time?

Not usually: This condition is common and generally not serious. They will generally heal with time, physical therapy and exercise to strengthen the core muscles. If this fails to improve with this over 8 or more weeks i recommend you get a surgical consultation from a neurosurgeon.

Most of us this: The research shows that 80% of people will have back pain in their lifetime. 75% of us are walking around with a spine pathology that is not bothering us at all so its very common. I would consult a fellowship trained spine/pain specialist to see your options. If you haven't tried epidural steroid injections first, that may be your best bet first.