Could be a few things.
I think you should try neck massage. If your neck can be out of place it might feel like it's your upper arm or shoulder that is the problem.
If you have been doing any heavy lifting. I would also not do that for a while.
You should go see your doctor if the pain persists.
Nerve pain is common and radiates from the neck.
Common causes of upper arm pain below the shoulder include muscle strains, tendonitis, rotator cuff injuries, bursitis, and nerve compression.
neck and left arm aches related to angina ,
What can cause severe upper arm pain (periodic aching between elbow and shoulder, sometimes pain going down arm and into shoulder)?
Pinched nerve in shoulder or c-spine
what causes shooting pain under right arm pit
hence, the funny bone
see a doctor
severe pain and swelling.
Left upper arm pain can result from various causes, including muscle strain, overuse, or injury. It may also indicate more serious conditions, such as heart issues or referred pain from the shoulder or neck. If the pain is persistent, severe, or accompanied by other symptoms like shortness of breath or chest pain, it's essential to seek medical attention promptly. Proper diagnosis and treatment are crucial for effective management.
Kittens
You would for sure on the lower arm to keep the arm raised to minimize swelling and pain. It will have no affect for the upper arm (above the elbow).
It sounds as though you may be having trouble with nerves being restricted in your neck. this can be the result of arthritis or some sort of trauma.