Hello and welcome to HCM,
I assume that the thickening of blood that you have mentioned is polycythemia
Polycythemia is characterized by increased viscosity of blood.
The cause is increase in erythropoietin
The cause of increased erythropoietin levels may be primary or secondary.
It is managed by phelebotomy and / or drugs e.g. hydroxyurea
The major complications of polycythemia is thrombosis and hemorrhage.
Thrombosis and hemorrhage can occur in any organ of the body.
Chills is unlikely to be due to polycythemia.
Labored or difficult breathing can be due to some kind of thrombotic process in the pulmonary circulation
Consult your treating hematologist
to investigate for the pulmonary symptoms.
Thanks and take care
Dr Shailja P Wahal