Have a bulge between my l5 and si. very painful to stand if sitting for more than a few min? sometimes fades after walk but sometimes persists.

Disc bulge: Actually, bulges are more "normal" than normal discs. I consider a bulge a problem only when there is compression of a nerve and symptoms that coincide with that nerve. Disc problems are typically worse with sitting/bending/twisting, and better when loads are decreased with standing or lying down. I question that your diagnosis is correct. Try pilates/piyo/yoga for core strength which may help.