Flu shot season is here – if you recently received a flu shot and have shoulder pain, you may be wondering how long will the pain last? Shoulder pain and soreness at the injection site immediately following a flu shot is very common and should subside within a few days. But what happens if it doesn’t? Shoulder pain that worsens or does not improve within the first few days following a flu shot may indicate a more serious condition known as SIRVA, or Shoulder Injury Related to