Possible COVID Vaccine Reaction  Introduction I am writing this because I think all of the issues described under the ?Current Situation? section may somehow be tied to an adverse reaction to my second COVID shot.  Until today, I had thought they were separate incidents with no common thread.  I now can see the possibility that they may be related.  I am asking for competent and engaged medical help to determine whether this is so, and if not, what the causes are for my issues.  I will give a brief medical history to give some current perspective.  Health History Current Vital Statistics ? Age: 66, Gender: Male, Height: 6?3?, Weight: 245  Hemorrhoidectomy ? In 1999 I had a hemorrhoidectomy to stop episodes of severe bleeding.  Heart Attack ? In August 2000 I had a heart attack, diagnosed as unstable angina, while on vacation.  They did further tests, found blockages and inserted stents in two arteries.  I was sent home with instructions to contact a cardiologist.  AICD ? After returning home, my new cardiologist did further tests and found evidence of ventricular tachycardia.  I was sent to a specialist who did an electrophysiology study and immediately implanted an AICD.  I have had it replace twice, with the latest one in April 2012.  It has never gone off.  There are close to five years left on my current battery.  Knee Replacement ? In January 2015 I had a total knee replacement of my right knee.  That was a result of several injuries and four surgeries, which left the knee without cartilage.  The knee replacement has worked flawlessly, and I am able to pursue athletics, especially playing tennis, without limitation.   Current Situation February 23 ? Received my first shot of the Moderna vaccine in my right arm.  Other than minor soreness around the injection site, I had no other reaction.  March 29 ? Received the second shot of the Moderna vaccine in my right arm.  Again, there was minor soreness around the injection site.  April 2 ? Had major pain in my tightness in my chest and major pain starting in my left shoulder and radiating down my left arm.  It caused significant discomfort, and I was awake a large part of the night deciding whether I need to call 911 for a possible heart attack.  I decided against that and instead went to urgent care in the morning (April 3).  My EKG was normal, my blood pressure was elevated (158/96 sitting, 157/91 standing).  Doctor could find nothing to suggest heart attack.  Prescribed a course of Prednisone for the shoulder/arm pain.  Had blood work ordered, which all came back normal.  April 5 ? Played doubles tennis as usual.  Noticed some weakness in my left shoulder and arm but played through it successfully.  The pain level was very low.  April 10 ? Played doubles tennis again.  From the first ball I hit I was aware of major weakness in my shoulder and arm.  They had no power at all, and I was almost unable to get my serve over the net.  I played through it again and played very poorly.  The interesting thing was that the pain and weakness did not worsen during the play or afterwards.  The pain remained after I had finished playing.  April 11 ? Chatted with the athletic trainer while I was officiating their women?s tennis match to look for clues as to what might be wrong.  He suggested in may be a shoulder impingement.  April 15 ? Had a phone consult with my primary care doctor.  I suggested the possibility of the shoulder impingement and he was willing to start there since this was a phone visit.  He referred me to orthopedics and physical therapy and prescribed meloxicam for pain.  The pain has continued unabated during this time.  April 21 ? Pain level was very high to the point where I was unable to work.  Went home and slept most of the day.  Meloxicam was not having much impact on the pain compared to my usual regimen of both acetaminophen and ibuprofen (which I had stopped using when I was taking the meloxicam).  After this I stopped the meloxicam and went back to the other drugs as required.  I had an initial visit with the physical therapist that afternoon.  She did not find anything which would suggest a rotator cuff or labrum injury.  Range of motion was normal.  She noted weakness in my left side compared to my right, which is unusual since I am left-handed.  She gave me three exercises to do daily.  April 23 ? Pain had been back to a more tolerable level.  I had a COVID test in the morning for a treadmill test I have next week, and also got an x-ray of my shoulder as requested by my primary care doctor.  After I went to bed, I had an incident of severe incident of chills which left me freezing and short of breath even with sweats on under my bed covers.  I called my wife in to check my vitals.  My blood pressure was a bit higher than normal but not critical.  My blood oxygen was 98 and my pulse was 70.  My temperature was 99.7 with an oral thermometer.  We called the after-hours nurse hotline and spoke with a nurse.  By that time, it had been about 30 minutes of chills and they were subsiding.  She said she would have a doctor call in the next couple of hours.  The doctor called back, and after going over everything, said to come in if the symptoms reoccurred.  Thankfully they did not.  All the while I am still having the pain in my left shoulder and arm.  April 24 ? Again, slept most of the day due to being worn out from the previous night issues and lack of sleep.  No change in the pain and discomfort.