The muscles will contract and you will have the feeling of stiffness and soreness. Muscle cramps can be caused by anything to extreme which causes the muscles to contract and relax. Muscle cramps can come up while you're exercising. Stop don't try to run through doing so increases your chances of seriously injuring the muscle.
When you get a cramp try to message the cramped muscle with one hand while you gently squeeze towards the center of the muscle try to feel how its contracted and stretch it in the opposite direction. Once the cramp passes don't start exercising right away. Walk for a few minutes to get the blood flowing back into the muscle then gradually return to the original activity and pace. Muscle cramps can sometimes be caused by a lack of potassium try eating a banana. Bananas are rich in potassium see if this helps to keep the cramps away.
If you know you have overworked your muscles try and take a cold shower this will help to help prevent swelling and soreness. You can try cold packs for twenty minutes at a time every hour. Cold helps prevent muscle soreness by constricting the blood vessels which will reduce blood flow and thus inflammation in the area.