upper arm pain

[James__0]

  I am an over 50 active male and a few months ago I began to have a dull pain about half way between my shoulder and elbow.  When I make a sudden move with my arm the pain is extremely sharp, otherwise it is somewhat dull.  It generally goes away during the day and returns at night particularlly when I lay down.  While holding my arm at rest there is no pain.  I just notice it when I move my arm into other positions such as trying to scratch my back, putting on a shirt or similar movement.  It is getting worse not better.
  I have started (last few days) using weights to exercise my arms.  What should I do now?
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Dear James:
As you would guess, the causes of arm pain are diverse, with very differing implications. Of the commoner causes, the most important one is angina, or pain related to ischemia of the heart from coronary artery disease. Angina is often exertional, such as with climbing three flights of stairs or running, or after meals. You do not volunteer any such history. The second common cause of importance is cervical radiculopathy, or a pinched nerve in the neck or cervical spine. In this situation the pain is often related to neck movement, or to coughing, sneezing, or straining. The third cause in order of importance is local musculoskeletal, such as a pulled muscle, or a shoulder problem.
The reliability of a clinical history and examination is good but not perfect in figuring these causes out, and tests are often needed to rule out a diagnosis of some seriousness such as angina. Other tests such as EMG can address possibilities such as a pinched nerve.
You should see your primary MD, specially if your pain is persistent or getting worse.