Talk to General Physician on Ankle Twist

I have a strange issue with my left foot. My ankle twists very easily. The first time it happened, i thought it would be fine a few days but my ankle has gone so weak that even a normally rough surface makes my ankle twist and believe me it causes excruciating pain. I am a boy age 21 and this pain is so intense that I feel my whole body shaking. Recently, I was hiking on a mountain in kalar kahar and there it happened again. It's been a weak or above since I returned home but this pain won't go. The pain is obviously very little and doesn't feel till I move my foot to left or right. I feel this pain from the ankle, a little way forward and then at the back of my foot. The bone is fine I don't feel any crack or swelling but day by day my foot is becoming weak and more vulnerable to easily getting twisted over the slightest rough surfaces. what should I do to reduce the pain and strengthen the tendons or muscles so it won't twist again ?