Work on getting the saddle in the proper position...height/fore-aft/tilt..making adjustments in tiny increments and giving each one a fair amount of riding time to determine if your tweak is better or worse. During that time you will also toughen up your butt. If after a reasonable amount of time you still have problems, look into a fit session and possibly a new saddle.
You really don't need bike shorts...but flat seams and wicking fabrics like polyester or wool will help, as will a tighter fit to keep the boys in place. If your shorts got them big sewn seams, they might ruin your day.
Anything worth doing involves a little pain at first...the folks that work through it have decades of enjoyment, those that don't have decades of regrets and excuses.