RepairPal Certified shops can diagnose and repair your 1998 Honda Accord. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
This should help, he covers multiple reasons. https://www.youtube.com/watch?v=xEDtqQ5MGd0
If none of this works then take apart the button in your shifter to see if it malfunctioning.