On a workout boost!

I have been going to the gym now every weekday for the past month. Each day I run on the treadmill--at first I was just running 20 minutes, not really looking for any kind of numbers. Just time. Then I started seeing that I was running 2.5 miles each day. I started clocking my times and noticed that I'm running an average of 8.5 minute miles. I'm now up to 3 miles each day. I never thought I would like running, but I have been loving this. I sweat enough to sink a small dingy and I feel really good about my workouts. After running I will work various muscles for another half hour. Thanks to Daft Punk and Rockstar for your assistance in all of this. I'm looking for a good pre-workout supplement. However, I tweaked a muscle in my back shoulder yesterday and I am in SO much friggin' pain. My range of motion is greatly limited at this time. I'm mostly upset because it's going to ruin this great boost I'm on right now. Here's hoping to keep with it!!