Shin pain and ankle weakness

Recently my right ankle has shown signs of weakness by "rolling" or giving out as I walk.  I don't fall but lose my balance.  It doesn't happen all the time but I never know when it will happen (walking down stairs).  Today I felt tenderenss when I rub my shin in my right leg.  Not sure if that is connected to the ankle weakness or not.  This is not caused by over-exercising.  Maybe exercising will help?

Thanks.