"Heartache"

I've been wondering, what exactly is it?

Is it your heart contracting from a sudden emotional stimulant, causing a physical phenomenon (such as sudden rise of blood pressure in your chest arteries) that brings about the "pain"? Is it your brain making up and sending that "pain" feeling from conceiving sadness? Is it physical, or is it like any other fantasy of yours, albeit a bad one?

it could be physical and mental at the same time i think. If the commercials for anti-depressants are correct, then believing youself to be depressed also causes pain throughout your body. This can be seen as a mental causation for the pain.

Heartache i would imagine to be the same thing. If you are hurt and seriously believe you are that hurt, you should also feel pain. Perhaps it is your minds way of telling your metal state physically?

I never believed in "heartaches" until I started having 'em mid-teenage years. It's like the veins near your sternum constricts, like the feeling you get when you're about to have diarrhea. I'm not sure if medical sciences have found out the reason for this discomfort (or whether its all in your mind) but it's not a "figure of speech"

Disclaimer: I have them when I "cringe" in general (seeing a puppy run over by a truck, seeing a girl get raped in movies, this). It's not the same as heartburns either (that's a stomach issue)

It's like you're sick with a cold except without the sneezing and the runny nose. You also get a headache that doesn't go away.

I believe it is the same as fear causing a quickening of the pulse. The mere thought of something dangerous causes the physical release of adrenaline, with its attendant physical effects.

The thought of something sad will make your tear glands work overtime, an easily observable physical reaction.

I believe "heartache" is the same. Being sad or "heartbroken" in your mental state causes an objectively measurable physical reaction. I don't know the details of that physical reaction, whether it's in the circulatory system or respiratory (which is the way it subjectively feels to me) or both, but I am sure it's not "all in your head".