In my opinion this sounds like normal discomfort when starting to learn.
I've found some good hand stretching exercises on YouTube, I'd suggest to stretch/massage your hands/wrist/fingers a couple times a day and really take your time and use good form when practicing. https://youtu.be/TSrfB7JIzxY?si=ZN6NSRwNqWqNRNC4
Justin, from Justin guitar, (definitely check him out if you haven't already) recently did a series of videos where he taught himself to play left handed. One of his main take aways that stood out to him was the pain you go through when first learning. So don't be discouraged it's a normal part of learning, just make sure your using the best form you can manage.
Be kind to yourself and remember this is a lifetime journey, not a sprint to a finish line. Practice at least a little everyday and focus on building a solid foundation that you can expand on the rest of your life!
Cheers and good luck!