I am 50 years male. For the last 5 - 6 months I have a pain in the ankle of my left leg on the upper side. It does not pain throughout but at times it pains. Sometimes it pains when I stand up from a sitting position and I feel disbalanced. The pain also occurs during walking and even when I lie down. The pain automatically subsides after some time. I do not have blood sugar or blood pressure. Apart from the above I am physically fit and have no difficulties even if I run. I do not take any other medicine. What is the cause of this pain? What medicine should I take or what exercise should I do?