What is this pain in my arm? PLEASE advise

[PamelaCake]

I shan't trouble a dr with this just yet but it's driving me mad

It's my right arm and the pain is EXACTLY the pain you get from a dead arm. Imagine someone gives you a great big punch on the upper arm and deadens it. That's what the pain feels like and that's where it is. Right in the centre of my upper arm.

It's not my shoulder and I have full range of movement. It's almost unnoticeable when I'm up and about doing things but as soon as I sit or lie down, it starts up.

It did come on after I did about 5 hours of repetitive work... packing 500 boxes. But I'm thinking that may have been coincidental.

Could it be a trapped nerve maybe ? Do you actually have them on your outer arm?? Heat doesn't do a lot and neither do painkillers

Seek emergency treatment if you have:
Arm, shoulder or back pain that comes on suddenly, is unusually severe, or is accompanied by pressure, fullness or squeezing in your chest (this may signal a heart attack)
An obvious deformity or protruding bone in your arm or wrist, especially if you have bleeding or other injuries.