DOMS stands for delayed onset muscle soreness…that muscle ache you generally feel c. 24-48 hours after a workout. And typically a workout that either follows a period of inactivity, is more intense that you’re used to or one that challenges you to use your muscles in a very different way.
It’s not specific to particular exercises, but it’s experienced more commonly when the muscles lengthen during the activity in question. The soreness you’re feeling basically is from the micro tears to your muscles that occur when you exercise, which then repair and become stronger when you rest.
It usually lasts a couple of days, it’s nothing to worry about and as your muscles adapt to your new routine and programming you’ll experience it less and less.
If you’re really struggling think about building up your programme more gradually, making sure you’re having sufficient rest and consider foam rolling, massage and an ice pack or ice bath.