I have been suffering from left-hand pain for the past year, breathlessness for the past four weeks, and chest pain for about two weeks, having severe pain in my left arm. My complete blood count showed my mean corpuscular volume. He meant corpuscular hemoglobin concentration was low, my red blood cell distribution width coefficient of variation was 16.9, and my D-dimer plasma level was 598. My thyroid level is 13.28. The doctor has prescribed me medicines for thyroid and iron tablets such as Feroz and Levothyroxine for thyroid. But still, my breathlessness continues. I do not have asthma; the electrocardiogram and echocardiogram screening were also normal. What could be the reason for my pain?