Imbalance

You could have muscle disease (myopathy) as a cause of your imbalance. There are many causes of myopathy, ranging from infections to autoimmune diseases. A detailed examination and muscle tests are necessary to diagnose myopathy, so see your doctor and be sure to mention all of your symptoms, including the part about the chair.

Just one more question.

Do you have joint pain, a sense of instability, or knee locking in one or both legs?

Yes, that's true for me.

No, I don't have those symptoms.