Thirty miles is a good start but you're still new. You need to put more miles on the bike and work up to longer rides.
As TH suggested, get decent shorts/bibs and swap saddles. Many bike shops have a test saddle program so you can try a saddle for a few weeks before buying a new one. How is your positioning on the bike?
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The Lord is merciful and gracious, slow to anger and abounding in steadfast love. - Psalm 103:8
I am a cyclist. I am not the fastest or the fittest. But I will get to where I'm going with a smile on my face.