A friend of mines wants to know what does it mean when you keep having sharp pains on your side or sometimes the middle of your chest it comes and goes frequently?

There are anatomic identification based on where pains are usually on evaluation. You may want to ask your friend to be evaluated for appropriate management. Pain in the middle of the chest may be from the heart, it may be from the lungs or just reflux in the esophagus. It may be from the kidneys or other organs depending on where on the side or it may just be from the muscles.