Brother, I'm no expert but I do know a fare deal about engines... And I'd say; Don't worry, the problem will vanish with the first oil change...
A brand new engine does get very heat-up during break-in period... It's because there are so many metallic particles and shards inside the crankcase and transmission that move around in the oil and cause excessive friction... Hence you're witnessing unusual heating issue...
After the first oil change, things will get a lot better in this regard as these particles will be flushed out with the oil...
Just don't rev the engine excessively & stay under the speed limit as prescribed in the user manual and you'll be fine... Also don't rev the engine when idle... Stay under 5,000rpms... And do change the first oil at the right interval, maybe even sooner if your budget permits it...
All the best...