I am 52 year old female. I have pain on the left side above and under my shoulder blade and my left arm feels odd - doesn't really hurt, just doesn't feel right. This started last night around 7:00 pm. Last night the pain was worse under my shoulder blade and my are felt like it was trying to go to sleep all the way down into my fingers. I have had a really bad headache every morning this week (which I thought was from the change in the weather). Do I need to see a doctor (or ER) regarding these symptoms?

Are you concerned about it? If it concerns you, you should see a doctor.

A woman having a heart attack might POSSIBLY have symptoms like this, although of course there are many things it could be. We don't know anything else about you! So please call your doctor and leave a message that you are going to the ER. If you don't have a doctor, please get one.

(Many here know that I seldom suggest the ER, but there is more and more evidence that women have unique symptoms when having a heart attack, and this is on your left side. And if you are able, could you let us know what happens, for the sake of others?)

It sounds more like you have a disc problem in your neck. That would cause all your symptoms. Although a heart problem CAN cause similar problems, it is highly unlikely without other signs/symptoms.
If it is a disc, it will gradually improve over the next week.