### Patient: Doctor, I have been experiencing muscle stiffness and tightness, along with a pale complexion. What could be the reason for this?
### Doctor: Based on your symptoms, it could be that you have leukemia. It is a blood cancer that causes abnormal white blood cells to grow and interfere with the normal functioning of other blood cells, which can lead to muscle stiffness or tightness, as well as pallor. We will need to perform some tests to confirm the diagnosis.