Can you help me work out what is going on?

Maybe this is logical and I cannot see it. Briefly: I had/have a serious depression, this has lasted for about 3 years now. During that period I became very inactive, for obvious reasons. Anyway, currently I am so keen to get back to the great physical shape I was in. More for the health benefits than the great body benefits.

Every time I go for a long walk my legs hurt like hell. I am not talking muscular pain but what seems like joint/bone pain.

My one ankle ‘plays’ up. Even without exercise. It just kind of goes stiff and I can’t bend it. Not always though. No swelling, no discolouration. Sometimes it kind of collapses. It is worse when I exercise or walk. I am walking much more than I used to, for a while now, but not everyday like I used to before. (Before the depression). I also get the urge to stretch my legs a lot?

Is it old age? Is it the period of inactivity? I know you don’t really know, but any ideas would help. I have to wait quite long before seeing a doctor and it’s not urgent.