I’m aching after exercising, is that normal?

Most definitely!  This is called DOMS which stands for Delayed Onset Muscle Soreness.  DOMS can take anywhere between 12 – 72 hours after exercise.  It is believed DOMS occur when there is small damage to muscle fibres.  Generally after a few days your muscle fibres will repair themselves, (protein is key to help with this) and you will be pain free….until the next time that is!