I get foot cramps since chemo. Docs didn't think it had to do with that so much, just to keep an eye on it and log it. My husband always says it has to do with potassium and to eat a bananna. My endurance is lower too, in general. My fears are higher, I won't ski or do rides at carnivals/amusement parks any more. My life has changed, alot. I'm more of a nervous nellie, less of a risk-taker.
As for smoking, I was able to quit and stay quit only after I tried Welbutrin, which got rid of the craving. I once quit for about 7 years and still craved it all that time. Then when 9-11 happened, I started that morning. When I convinced myself that my asthma was going to kill me if I smoked, I was able to quit. I think what really helped was using the Welbutrin, though, because the craving was gone. There is a new drug called Chantix that I hear really is good. You may want to ask about it if you're interested.
I'm sorry you have pains. If anybody knows more about the foot cramps, please post, I'm interested.