This may sound dumb but I just starting riding primarily for exercise purposes and my butt is extremely sore from the seat. Can a new after market seat truly make a big difference in comfort or should I try and wait until I get used to it. Thanks for your help in advance.

Squid

The answer to your question is a YES! A GOOD quality saddle will make a big difference. SERFAS makes some exceptional saddles, but there are others. Don't buy cheap. Expect to pay $50. and up.
The other thing you need to know is that it takes time for that area of the anatomy to get used to the abuse riding does to it. Good PADDED shorts are also a must. Again, expect to pay $50. and up.
If you are embarrassed by the look of them wear some sweats or loose shorts over them. Good luck. Keep riding. It will get better, but don't expect over-night miracles even if you spring for a new saddle and shorts.

your're always gonna get sore when starting out, 'till your butt gets used to riding

Try some "chamois" shorts, and be sure to wear them next to your skin with nothing underneath. No matter what saddle you use you'll get sore anytime you wear something that has seams under your crotch.

Yeah,

We all go through this at some point in time. The quickest remedy I have always found, is to bite your teeth, just keep going and sit through the pain. After approximately 10 long rides, your but adapts and the problem disappears.

Good luck,

Snowplug
https://www.exclusive-cycling.com