turmeric helps

my neck causes this all the time, it's painful also, may want to tell the doctor about this one though, the heart you feel in the left arm also. Turmeric is a very good supplement to try.

You probably slept on it

No need to be scared. Now that you told us about the raised arm, that's what caused it. This is not dangerous, it a very common thing that happens to all, healthy and less healthy

CALLI...do you sleep with your arms bent so your hands are up under chin? I do, and my dr said not to do that so they will be numb, he said not to bend your arms more than 90°, he gave me these braces to wear at night on my hands and arms, I tell you it's very difficult and very cumbersome, maybe try to sleep with you arms straighter and see if that helps.