Welcome to health care magic.
1.There is a disc between the
vertebral bodies helps as a
shock absorber effect, the disc contains maximum percentage of water, due to degenerative changes when the water content / hydration is lost the disc slips / bulges.
2.In your case bulge is at L4-5,L5-S1.
3.Causing mass/pressure effect on the
nerve at L5-S1 and Chord compression at L4-5.
4.There is inflammatory change seen in the vertebral joint space at level of L4-5,L5-S1 level.
6.Treatment in this case is exercise followed by
physiotherapy.
for exercise follow this link. good luck.
http://www.nhs.uk/Livewell/Backpain/Pages/low-back-pain-exercises.aspx
Hope i have answered your query.
Any thing to ask do not hesitate. Thank you.