Originally Posted by
SLA
Sounds like you are just a bit on edge, and getting into a panic.
You wouldn't ever feel your heart 'twitch'. But if that is what you thought, then that would trigger panic, and get your heart racing.
That can occasionally cause pain and discomfort.
Cyclists call it going into the red. Its when your heartrate spikes, and gets close to max BPM. It happened to me a few weeks ago, and I was definitely in pain for a little bit!
Its nothing to be concerned about. Try to relax.