Returning to the gym. Muscle aches. Ow!

Hey,

I'm Blake. 25 years old. Just got a membership to the YMCA and had a consultant with a trainer. I commited to doing this bootcamp class 3x a week and one day of yoga. I'm struggling with extreme muscle aches and pains to the point I can't even walk up a flight of stairs. Any tips for a new guy for pre/post workout? Drinks, foods, techniques to reduce some of the muscle aches?