How Normal is Forearm Muscle Soreness?

Been practicing for about 5 months very consistent. I get in about an hour a day broken down into 10-20 min chunks. I recently started increasing how long I practice (about 70-90 mins) and I’m focusing on chord changes and barre chords.

I am finding some forearm soreness and a little bit of thumb soreness. It feels more like I worked out and the muscles are sore but not in a bad way.

Is this typical especially for a beginner? Should I reduce how long I’m practicing? Is this a sign of bad posture or too much tension?

I’m focusing on not fretting hard and I keep my thumb positioned behind my index/ middle fingers on the back of the neck.