As others said, see if adjusting the saddle first helps.
Next I'd go with a good pair of shorts. Don't get cheap shorts nor spend $150 for a pair just yet.
Two tips:
#1 Avoid thick gel shorts. They fell good at first but then the gel starts migrating to where you don't want it.
#2 The shorts should be snug. Loose shorts can bunch up in the wrong places.
Another thing: How often do you stand up off the seat? Do this frequently. Maybe make every little hill a reason to stand up on the pedals.