does pain in my left arm mean heart attack ?

it could be, see a doctor at once. take no chances.

No.  Go to the ER.  Now.

Not all left arm pain, achiness or difficulty moving is a sign of a heart attack. Sometimes the cause is an injury, compressed nerves or other issues that don't involve your heart. Be mindful of the other symptoms, and if they last for more than a couple minutes, get emergency help.

If heart related you also have chest pain at the same time.

I'd get it checked out

Yes.  Go to your ER immediately.

Heart attack is a crushing pain in your chest, lack of breathing, sweating and then pain in the arm up to the neck.

You have muscle strain.

Heart attack can cause arm pain. So can pinched nerves, pulled muscles, bruises, arthritis, .....

No one here can determine what the cause of your intermittent arm pain.