Greelydia is right. I would lean towards tendonitis, rotator cuff or AC joint. I had my rotator cuff operated on because the aching and burning became intolerable. It would spread down my whole arm and out into my collarbone. It was my left shoulder so the pain matched some cardiac symptoms. Of course after the MRI there was no doubt about the torn rotator cuff. Ask your doctor to investigate the arm pain. It would at least set your mind at ease over the heart worries.
You've seen a number of doctors since this original numbness happened 4 months ago. All of them have concluded that it's NOT cardiac in nature, but is presenting more as a pinched nerve, a pulled tendon or ligament. You need to beleive them! No doctor is their right mind is going to send someone with cardiac symptoms home to "see what happens."
There are actually many things that could be causing your symptoms. You could have injured your rotator cuff, (in your shoulder) your neck , your back, your arm even! (DOH) It is so easy to really hurt ourselves and not know it for days and sometime weeks, which makes us think this just happened virtually overnight, It can take that long for inflammation to reach the point of piching a nerve, if a muscles/tendon/ligament has been pulled, tweaked or twisted, it may only cause the numbness when it is irritate/swollen/overused............
Long response getting shorter..............as for the recent jaw pain which you are immediately attributing to a heart attack, please consider what I think is the cause. With your increased anxiety, you have probably joined the ranks of those of us who clench or grind our teeth in our sleep. This is so common and why TMJ is becoming big business in the Dental industry.
Jaw pain associated with a heart attack is almost always accompanied by other symptoms. Very rarely is it the ONLY symptom.
Aside from an increase in anxiety, are there any other symptoms that happen when you feel this numbness?
In my humble and non-medical opinion, I would suggest making an appt. with and orthopedic. They will be able to rule out.........or in........ any structural damage to your bones and joints that could be causing this numbness. If they find nothing, they will know who next to send you to. Sometimes it does take a village to raise a child and sometimes it takes the whole damn hospital to find the cause. Which they will. I promise.
You are not crazy. But ya know something? Lately I've been feeling like in this day and age, that just might be an advantage! LOL
You're going to be fine. Try to stay calm, relax when you can.
Peace
Greenlydia