Injection site was at 1 cm below the acromion.  Initially, pain (level 4 or 5 out of 10) in shoulder joint when arm was raised backward 30 degrees, raised sideways 180 degrees, raised forward 90 to 135 degrees, or raised to the side 90 degrees (horizontal) and rotated forward with thumb pointing to ground.  Injection site itself never had any redness or swelling.  There was initially some soreness in about a quarter-sized spot around the injection site for the first three or four days.  The deltoid muscle never became sore all over like it usually does.  My parents who are retired medical doctors, both GPs, looked at the injection site the day after I got the flu shot and said it looked too high to have hit much muscle, if any. I thought it felt like the initial injury was starting to get better by 9/4 (the third day); the pain was starting to decrease though I was starting to feel a bit of stiffness and tightness (which eventually started to decrease on 9/12), and at night there was an odd sensation as though the back half of the head of the humerus was covered with something that wasn't normally there, like plastic wrap. I think that persisted for a couple of days.  On 9/5, I went to the orthopedist for a 9:45am appointment, but the pain at this point was pretty minimal, probably a 1 out of 10. The orthopedist had never seen a shoulder injury from a vaccine before, and since it appeared to be healing I probably wouldn't have to worry unless it worsened.  He said the structures under the injection site like tendons and bursa were pretty tough so perhaps there was a good chance the needle hadn't penetrated.  From 9/5 to 9/9, the shoulder was about the same, not that much pain (1 out of 10), but with the feeling of stiffness remaining.  On 9/10, the pain started to increase a bit, and increased again on the next day and the day after.  At maximum pain, I suppose maybe a 4 or 5 out of 10.  I found a web page describing a physical exam for rotator cuff injuries, and I seemed to have pain during all of them except raising the arm horizontally to the side and pressing down on it (supraspinatus test, I think?) Some movements have been consistently painful throughout the whole course of the injury, though not always to the same degree, like raising my arm forward above 90 degrees through 135 degrees or sometimes higher.  Also when my arm is raised horizontally to the side and rotated forward to thumb pointing to the floor.  Other pains seem to come and go, like sometimes when I raise my arm sideways from 60 to 90 degrees, like I've seen described for subacromial bursitis. Advil (200 mg) seems to help when that happens. Sometimes my shoulder hurts when raised sideways above 90 degrees too, though the descriptions I found for tendinitis and bursitis mentioned a relief of pain during this motion.  On the first three days and also on 9/13 and 9/16, I had some pain when moving the arm backward, and also various directions that seem to come and go, sometimes disappearing when I try to repeat a movement that caused pain a moment ago.  It felt like there were sore tendons on the front and back of the head of the humerus at those times.  I think they're the biceps tendon, the teres minor and maybe the infraspinatus.  Heat treatment seemed to be more effective than Advil for those.  The condition of my shoulder has been fluctuating from day to day since 9/10.  There's been decreasing in pain over the last three days in a row.