I have had a spinal disc problem (l4-l5) and terrible pains for more tha 20 years now, does it get worse to the time that i won't be able to walk?.thx

Not necessarily: I do not know if the disc problem is the cause of your chronic back pain. Regardless , if the l45 issue is degenerative, whether it will progress or not is variable. It may not.

Rare but possible: Typically without anything compressing your nerves like herniated discs or bone spurs. And without spinal stenosis, symptoms will like be restricted to your back. You must watch out for any changes in your bowel or bladder function, as that could imply an emergency. You need to be evaluated by a spine surgeon, to inform you of your specific diagnosis. There are lots of effective treatments.