Why is my Amazon EC2 instance "pending"?

Pending means the instance is being created, if it has been like that for 30 minutes something went wrong, typicaly I wait for 3 minutes.

I would just create another instance and when the pending one is over, terminate it.

you would probably waste 12.5 cents tho...

I recently faced the same issue. After reaching out to AWS support, they provided a workaround which worked well.

You can use the AWS CLI to stop the instance, instead of AWS console. Although an instance stack in Pending state cannot be managed through AWS console, using the AWS CLI allows you to stop it and start it again. The following command should allow you to stop the instance and force it move to the "Stopped" state:

aws ec2 stop-instances --instance-ids <You instance Id>

You can find more information about how to install and use AWS CLI here: https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2.html