What Is The Treatment For Ankle And Knee Pain?

I am 47 yrs old. Last spring I had a high ankle sprain and wore a brace for 2 weeks. It seemed to have improved over time. But recently when I walk, mostly first thing in the morning, I feel this odd pull in my ankle that feels like something is being pulled out of place then back in.I compare this to like a peg being pulled out of a hole then pushed back into the hole. I also have been experiencing horrible knee pain on that same leg and am unable to straighten it completely without pain. When I do manage to straighten it, when I go to bend it again, it has this horrible pop laterally and hurts severely. The pain radiates doen my tibia to my foot. This radiating pain happens with I am sitting doing nothing also. Occasionally, this knee tries to hyperextend. A lot of my work consists of walking and lifting items up to 50 lbs. I am not sure the ankle and knee are related to the same injury.