i keep on feeling my heart is thumping hard in my throat...is this the sign of panic attack??

[Biglips]

?????????????????????

I know when I have had them, I've been convinced I was having a heart attack - no pain, but tight chest, heart pumping away, hyperventilating. It's not pleasant.

my chest is fine but it just comes on out of the blue...been having them on and off for the past few years but today its had been all day

Maybe worth seeing the GP? I find these things self-perpetuating though. You feel anxious and start feeling funny, because you feel funny you feel more anxious and so it goes. Can you try relaxing and see if it makes it better - warm bath, gentle music, glass of wine?

My first thought was hyperthyroidism.

This bit in Wiki sound similar.

"Thyroid hormone functions as a stimulus to metabolism, and is critical to normal function of the cell. In excess, it both overstimulates metabolism and exacerbates the effect of the sympathetic nervous system, causing "speeding up" of various body systems, and symptoms resembling an overdose of epinephrine (adrenalin). These include fast heart beat and symptoms of palpitations; nervous system tremor and anxiety symptoms; digestive system hypermotility (diarrhea), and weight loss."

Panic attacks are similar in terms of some symptoms but of course a quite different cause.