My knees just won't heal!

I have been trying to get in shape for about a month. Running a mile, push ups, sit ups, most in-home excersizes. Usually I run a mile in about 10 minutes.(Which isn't bad for never running much)I've got a high school track next to my house so i can go whenever I want. Usually I jog about 2/3 of a mile and walk 1/3(spacing out proportionally) Thursday morning, about 5 days ago, I went to run a mile, and I actually jogged the whole mile. I felt pretty good about it and didn't ache much until nighttime. Since then, especially Saturday, I've not been able to jog or stand for more than an hour without out pain in my knees. When I sit down after long days of work my knees down to my feet throb and are in pain for about 15 minutes. I found that if I push around my knee cap it's really tender and hurts like hell! Especially the inner most area closest to my feet. I'm not sure what I did or what to do. I can't jog without pain anymore and I have had several days to recuperate. Starting to feel like crap again because I'm not excersizing how I would like to. Any tips on the pain or healing process??