A few days after my 2nd Pfizer dose in April, 2021, I developed a lump on my collarbone. The doctors suspected the cause was the vaccine but ordered blood tests and an X-ray. The X-ray was negative but the blood tests showed greatly decreased iron levels. That led to a CT scan, endoscopy and colonoscopy, all of which were negative for any internal bleeding. During the next few months I was very fatigued but eventually my iron levels went back up and so did my energy level. The doctors indicated the drop in iron levels was because of too frequent blood donations! I’m 61 years old and have donated blood since I was in my early 20’s and this was the first time my iron levels ever went below the normal range.