Well I first did yoga many many years ago when I was a tree hugging hippy vegetarian. I have no clue how I was ever a vegetarian anyway.
Ooo thats interesting! wow so you were one of those vegetarian types back in the day...it musta been rough. Eating meat is definitely key. My mom was a huge hippie all her life and she's still really environmental and organic and all that, so when I was in high school she decided she was going to cut back drastically on the meat she made for dinner, but I protested so much that it didn't last very long lol. At least one good thing came out of it for you: Yoga!
When I got heavy into left weights 4-5 years ago. I was younger and had no problems going into things cold never stretching before or after workouts but then something happened

I started getting older

lol
at that. Warming up and stretching is super important thats for sure After my first contest prep I end up with a whole lot of aches and pains. I started to see a chiro/ART guy and he gave me many stretches and exercise to help. At first me being stubborn I didn't do them.

Then he was like look SuperQT if you don't start doing them your going to have to depend on my through your contest prep at $50 a pop I didn't want to depend on him.
ouch! 
So I started doing the things he told me. He also told me to hit up some yoga and or pilates type classes. I started doing that after I was all healed up and I didn't see him one over my last contest prep been months since I seen him actually. So the long wind way of saying I like it because it has greatly decreased the aches and pains I used to experience. Plus I find the classes extremely relaxing they center me clear my mind and I am totally in the moment when I am on the mat which is great the only other time I can focus like that is lifting. The thing is with lifting it is more high energy a lot of anger and aggression is used there with yoga it is a total state of peacefulness myself and the world around me.