About your knee problems, it could very well be caused by the fact that you aren't fit. You gotta have some muscles around your knees. Thighs are important, but you have got to take away some pressure away from your knees.

I am not a doctor, but I used to be a runner and I can tell you pumping up all your QUADs solve about a half of your problems. You know, leg extension exercise. It is probably one of the most infernal exercise in the gyms, but you gotta do it. (The leg exercises I hate most were squads and cleans. Oh lawdy. They are super dangerous and super embarrassing. Don't do those without supervision.)

However, in rare case, you may be in a deep deep problem. Feel your knee caps and see if they move smoothely as you bend and straighten your legs. If you feel resistance or sandy, you better go see doctors. This could mean you have deposits in your knee cap. This could only become worse and cost you a lot of money.

Hey take care, OK? Knee pains are extremely serious. Some people are permanently screwed and had to wear knee supporter for the even easiest of daily chors.

T