My doc saw on my mri that i have arthritis in my back (l14 and l15). can this arthritis cause leg pains?

Yes: Osteoarthritis of the lumbar spine can cause leg pain.

Definitely: If the arthritic changes compress a spinal nerve root, they can cause pain in the areas supplied by that root. L4 and l5, in particular, are responsible for sensation down a significant portion of the legs. Depending on the nature of the compression, physical therapy or medication to reduce nerve activity can be helpful with these symptoms.