If I had a high ankle sprain and a torn tendon 4 months ago and it still hurts, what should I do to alleviate the pain?

Have it evaluated. It is common for one to experience pain for several months following an ankle injury. An MRI may be of benefit in diagnosing your pathology.
Get it diagnose. To know what is the problem then we could advise you. May be you need MRI on the ankle to see if there is something broken in the joint or if the ligament healed or not.