Pain in hands/forearms

Sounds like you are placing too much wieght on your drops. For best hand comfort you should be almost neutral on your hands. Some soreness may be normal until you get accustomed to riding, depending on your lifestyle.
The simplest way to relieve hand stress is to adjust your saddle tilt. It is very common for new riders to have thier saddles tilted forward in hopes of releiving "other" areas😉. You would be surprised at how much above level you can tilt and get used to. I use about 10 deg positive on the MTB and 5deg positive on the road. Adjust in small increments(sometimes post clamps have notches, go by 1-3 clicks) and ride a couple times on each before changing again. Once you have it you will know.

Any physical activity, such as cycling, will cause muscle pain when you over-extend yourself. Since you are new you are feeling the effects of holding your weight up and keeping your hands in one position for too long. Given time in the saddle you will become a stronger rider and you won't come home with sore muscles.

There are a number of reasons why your forearms and hands are sore. One may be that your bike fit is not optimal and you are stretched too forward while riding, which is a common problem for new riders unfamiliar with how important proper reach is. The muscles in your arms are not used to holding your weight up while cycling and if your seat is too high relative to the handlebars that could also be a reason too much weight is on your hands.

Don't let being sore put you off from riding. Ride more frequently for shorter rides and gradually increase your time on the saddle. Like any activity, in time you will be able to look back to where you were and feel good about how much you have improved.

ScoJo said:

I am a new rider. On Sunday I went riding with a friend. We did about 12 miles in about an hour. At that point I had to stop because of pain in my hands (between thumb and forefinger where I happened to be resting on the brake hoods).

Today I am having a good amount of pain, but basically in the tops of my forearms.

What is causing this? Is it that I am gripping too hard? Is there a bike adjustment that I need to make? Is it just something that goes away with time? I could have gone longer, but this is kinda disappointing.

Thanks,
Scott