Can Severe Anemia Cause Knot Under Armpit?

I have a low hemoglobin, it was 5 in Nov. got a blood transfusion came up to 8 went on integra instead of iron supplement I've been on for 3 yrs. I also have low iron, tried iron infusion few days ago (infed) had a bad reaction to test injection had to stop. I have a huge knot under my armpit I just noticed could it be related to my severe anemia? Should I show DR.