Ouch! Sore arms, burning thighs

Working the shoulders. (I don't have any pictures of me doing the Butterfly Press or Chest Press.)

On Monday I did about 45 minutes of hills on the espinner at the work gym. After that I did a little bit of weights for my arms. I did the Butterfly Press and Chest Press. I also did some tricep work.
I skipped exercise yesterday as I had a work dinner to attend. But my arms were sore, especially where the armpit kinda is. Ouch! Whatever that muscle is where the shoulder meets the under arm? (According to this link, it looks like what I am trying to describe is part of the pectoralis major.)
Today still a little sore. I attended my regular Hatha Yoga class with Baxter at Namaste and I could really feel it in my arms and shoulders today when we were in particular poses. Man, the burn.
Also for some reason my thighs were on fire. Though that is a pretty regular occurrence when in particular yoga poses for more than what seems likes hours, but it is probably only 30 seconds, maybe a minute.