fast metabolism confused for being fit

This would be the case of me.
I am being pushed a little harder due to my build (long and lean but not limber in the least).
I've got long legs that are not as bendable as they look!
I have never pushed my body physically, so all this exercise, stretching, twisting, sprinting..., well, feels like I'm doing some relatively permanent damage to my body.
Perhaps I'm being a tad bit overdramatic here. I'm not gonna lie, I LIKE being picked on.
I want to kick major ass, and I can't do that unless I get my ass majorly kicked in preparation, LOL

Injuries?

-knee/inner thigh (groin)/foot pain on right side...related injury or seperate?
-skating knock-kneed, research "Q angle"; I may be putting unneeded strain on the knees.

Garbage Gut

With all this hard work, it's tough for me to pig out as I have done my whole life thru.
It's different when you work so hard at something and then pissing it all away with something like a horrible diet.
I am a foodie to the extreme, so this may prove to be more difficult than an eternity of push-ups.
I don't think I'm ready to let up on the butter just yet, but I will cut out the refined sugars, at least.
Baby steps!