A magnesium deficiency can cause twitching in your legs, but I don’t know if anyone on the internet would be able to help tell if the pulsing sensation is caused by muscles contracting or something else.

If you have decent access to healthcare and it’s bothering you, bring it up with your doctor. It’s unlikely anyone here is qualified to be giving you medical advice. And if they were, they likely wouldn’t be comfortable giving a diagnosis based only on a post.

I have heat pumps in some rooms (mainly for cooling) in the lower Hudson Valley, New York. Mine aren’t effective at heating the house when temperatures fall below 50 F. But my house is almost 100 years old and extremely drafty, so it may not be the best point of comparison.